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diff --git a/old/67287-0.txt b/old/67287-0.txt deleted file mode 100644 index ca2b55c..0000000 --- a/old/67287-0.txt +++ /dev/null @@ -1,6488 +0,0 @@ -The Project Gutenberg eBook of Relics of Primeval Life, by Sir J. -William Dawson - -This eBook is for the use of anyone anywhere in the United States and -most other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms -of the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you -will have to check the laws of the country where you are located before -using this eBook. - -Title: Relics of Primeval Life - Beginning of Life in the Dawn of Geological Time - -Author: Sir J. William Dawson - -Release Date: January 30, 2022 [eBook #67287] - -Language: English - -Produced by: Tom Cosmas produced from materials provided at The Internet - Archive and placed in the Public Domain. - -*** START OF THE PROJECT GUTENBERG EBOOK RELICS OF PRIMEVAL LIFE *** - - - - - -Transcriber Note - -Text emphasis displayed as _Italics_ and =Bold=. - - - - - RELICS OF PRIMEVAL LIFE - - - +------------------------------------------------------+ - | WORKS BY | - | | - | Sir J. William Dawson, | - | | - | LL.D., F.R.S., etc. | - | | - | =Eden Lost and Won.= Studies of the Early History | - | and Final Destiny of Man, as taught in Nature and | - | Revelation. 12mo, cloth $1.25 | - | | - | The work is in two parts. Part I. considers the | - | physical and historical probabilities respecting the | - | authorship and authority of the Mosaic books. Part | - | II. treats of man and nature, fallen and restored. | - | | - | =The Historical Deluge.= Its relation to Scientific | - | Discovery and to Present Questions. 12mo, boards .25 | - | | - | "It is a very satisfactory statement. Will be very | - | useful."--_The New York Observer._ | - | | - | =The Meeting=Place of Geology and History.= | - | Illustrated. Lowell Lectures, 1894, 12mo, cloth 1.25 | - | | - | "We commend these lectures heartily to all who | - | are anxious to have a clear understanding of this | - | important discussion."--_The Living Church._ | - | | - | =Modern Ideas of Evolution as related to Revelation | - | and Science.= Sixth Edition, Revised and Enlarged. | - | 12mo, cloth 1.50 | - | | - | "Dr. Dawson is himself a man of eminent judicial | - | temper, a widely read scholar, and a close, profound | - | thinker, which makes the blow he deals the Evolution | - | hypothesis all the heavier. We commend it to our | - | readers as one of the most thorough and searching | - | books on the subject yet published."--_The Christian | - | at Work._ | - | | - | =The Chain of Life in Geological Time.= A sketch of | - | the Origin and Succession of Animals and Plants. | - | Illustrated. Third and Revised Edition. 12mo, | - | cloth 2.00 | - | | - | =Egypt and Syria.= Their Physical Features in | - | Relation to Bible History. Second Edition, Revised | - | and Enlarged. With many Illustrations. _"By-Paths of | - | Bible Knowledge." Vol. VI._ 12mo, cloth. 1.20 | - | | - | ---------------- | - | | - | =Fleming H. Revell Company= | - | | - | New York: 112 Fifth Ave. | - | Chicago: 63 Washington St, | - | Toronto: 140 & 142 Yonge St.| - +------------------------------------------------------+ - -[Illustration: Cryptozoon Boreale, _Dawson_.] - -Two divisions or branches of a large specimen collected by Mr. E. T. -Chambers in the Ordovician of Lake St. John. (See Appendix D.) - - [_Frontis._ - - - - - RELICS OF PRIMEVAL LIFE - - BEGINNING OF LIFE IN THE DAWN OF GEOLOGICAL TIME - - - BY - - SIR J. WILLIAM DAWSON LL.D., F.R.S., Etc. - - - - _WITH SIXTY-FIVE ILLUSTRATIONS_ - - - - [Illustration] - - - NEW YORK CHICAGO TORONTO FLEMING H. REVELL COMPANY - - 1897 - - - _The substance of a Course of Lectures on Pre-Cambrian Fossils - delivered in the Lowell Institute, Boston, in November, 1895._ - - - To - - AUGUSTUS LOWELL Esq - - _Vice-President of the American Academy of Arts and Sciences - - Trustee of the Lowell Institute_ - - - AS THE WISE AND LIBERAL ADMINISTRATOR OF A NOBLE - - ENDOWMENT FOR THE ADVANCEMENT AND DIFFUSION - - OF KNOWLEDGE - - - THIS WORK IS DEDICATED - - WITH MUCH RESPECT AND ESTEEM - - BY THE AUTHOR - - - - -PREFACE - - -IT is now more than thirty-five years since the announcement was made -of the discovery of remains supposed to indicate the existence of -animal life in the oldest rocks known to geologists. It was hailed with -enthusiasm by some as "opening a new era in geological science"; but -was regarded with scepticism by others, in consequence of the condition -and mineral character of the supposed fossil, and because of the great -interval in time between the oldest animal remains previously known and -these new claimants for recognition. Since that time, many new facts -have been learned, and the question has been under almost continuous -discussion and debate, with various fortunes, in different quarters. - -The author was associated with the original discovery and description -of these supposed earliest traces of life; and has since, in the -intervals of other work, devoted much time to further exploration and -research, the results of which have been published from time to time in -the form of scientific papers. He has also given attention to the later -discoveries which have tended to fill up the gap between the Laurentian -fossil and its oldest known successors. - -In 1875 he endeavoured to sum up in a popular form what was then known, -in a little volume named "The Dawn of Life," which has long been out of -print; and in 1893 the matter was referred to in a chapter of his work -"Salient Points in the Science of the Earth." In 1895 he was invited -to present the subject to a large and intelligent audience in a course -of lectures delivered in the Lowell Institute, Boston; and the success -which attended these lectures has induced him to reproduce them in the -present work, in the hope that inquiries into the Dawn of Life may -prove as fascinating to general readers as to those who prosecute them -as a matter of serious work, and that their presentation in this form -may stimulate further research in a field which is destined in the -coming years to add new and important domains to the knowledge of life -in the early history of the earth. - -Hypotheses respecting the introduction and development of life are -sufficiently plentiful; but the most scientific method of dealing -with such questions is that of searching carefully for the earliest -remains of living beings which have been preserved to us in the rocky -storehouses of the earth. - -There are many earnest labourers in this difficult field, and it will -be the object of the writer in the following pages to do justice to -their work as far as known to him, as well as to state his own results. - - J. W. D. - - - - -CONTENTS - - - I - - PAGE - - The Chain of Life Traced Backward in Geological Time 3 - - II - - Life in the Early Cambrian 17 - - III - - Pre-Cambrian Life 47 - - IV - - Foundations of the Continents, and their General - Testimony as to Life 79 - - V - - Probabilities as to Laurentian Life, and Conditions - of its Preservation 107 - - VI - - The History of a Discovery 125 - - VII - - The Dawn of Life 147 - - VIII - - Contemporaries of Eozoon 193 - - IX - - Difficulties and Objections 221 - - X - - The Origin of Life 245 - - XI - - Some General Conclusions 281 - - -APPENDIX - - A. Geological Relations of Eozoon, etc. 295 - - B. Organic Remains and Hydrous Silicates 298 - - C. Affinities of Eozoon, etc. 303 - - D. Cryptozoon 310 - - E. Receptaculites and Archæocyathus 315 - - F. Pre-Geological Evolution 320 - - G. Controversies respecting Eozoon 324 - - H. Notes to Appendix, December, 1896 329 - - - - -LIST OF ILLUSTRATIONS - - - FIG. PAGE - - Cryptozoon Boreale _Frontispiece_ - Map xvi - 1. Olenellus 20 - 2. Triarthrus 23 - 3. Hymenocaris 27 - 4. Ctenichnites 32 - 5, 6. Archæocyathus 35 - 7, 8. Cryptozoon 37, 39 - 9. Fossils in Lower Cambrian Boulder 41 - 10. Section Hanford Brook 51 - 11. Worm Tracks 53 - 12. Pre-Cambrian Fossils 54 - 13. Arenicolites and Aspidella 54 - 14. Cryptozoon 56 - 15. Worm Burrows 67 - 16. Casts of Foraminifera 68 - 17. Tudor Eozoon 69 - 18. Laurentian America 85 - 19. Map of Grenville Limestones 88 - 19A. Attitude of Limestone, Côte St. Pierre 91 - 20, 21. Disturbed Beds 103 - 22. Section of Limestone 113 - 23. Silicification of Coral 113 - 24. Cast of Polystomella in Glauconite 115 - 24A. Crinoid and Shell in Glauconite 116 - 25. Nature-print of Eozoon 121 - 26, 27. Eozoon from Calumet 130 - 28, 29. Canals of Eozoon 133 - 30, 31. Canals and Tubuli 135 - 32. General Form of Eozoon 149 - 33, 34. Eozoon with Funnels 152, 153 - 35. Small Specimen and Structure 155 - 36. Decalcified Eozoon 157 - 37. Finest Tubuli filled with Dolomite 158 - 38. Arrangement of Canals 159 - 39-41. Finest Tubuli 160-2 - 42. Canals after Möbius 163 - 43. Stromatocerium 172 - 44. Stromatopora 173 - 45. Cœnostroma 174 - 46. Recent Protozoa 176 - 47. Fragmental Eozoon 183 - 48, 49. Nummulites and Calcarina 186 - 50, 51. Archæospherinæ 190, 200 - 52. Acervuline Eozoon 205 - 53, 54. Archæospherinæ 205, 208 - 55. Ditto, Finland 212 - 56. Eozoon Bavaricum 213 - 57. Archæozoon 215 - 58. Restoration of Eozoon 230 - 59. Eozoon in Different States 237 - 60. Nature-print of Large Specimen _To face_ 296 - -[Illustration: _Walker & Boutall SCt_ - -Grenville Series on the Ottawa River (17 miles to an inch). - -_From Logan's Original Map of 1865._] - - -_THE CHAIN OF LIFE TRACED BACKWARD IN GEOLOGICAL TIME_ - - -GEOLOGICAL CHRONOLOGY OF LIFE. - -_After Prof. C. A. White._ - - =Column Key=--_Using First Letter_ - ---------------------------------------- - Invertebrates. Vertebrates. Plants. - -------------- ------------- --------- - Protozoa Ganoid Fishes Algæ - Corals, etc. Telios Fishes Land Cryptogs - Echinoids Batrachians Phænogams - Worms Reptiles - Mollusks Dinosaurs - Arthropods Birds - Insects Marsupials - Land Snails Placentals - Humans - - Geological Invertebrates. Vertebrates. Plants. - Systems or - Periods. P C E W M A I L G T B R D B M P H A L P - +------------------------------------------+ - Kainozoic. | ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖| - { Cretaceous ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖| - { |-‖-‖-‖-‖-‖-‖-‖-‖--‖-‖-‖-‖-‖-‖-‖------‖-‖--| - { Jurassic ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { |-‖-‖-‖-‖-‖-‖-‖-‖--‖---‖-‖-‖---‖------‖-‖--| - { Triassic ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - |-‖-‖-‖-‖-‖-‖-‖-‖--‖---‖-‖------------‖-‖--| - Palæozoic. | ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { Permian ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { |-‖-‖-‖-‖-‖-‖-‖-‖--‖---‖--------------‖-‖--| - { Carboniferous ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { |-‖-‖-‖-‖-‖-‖-‖-‖--‖------------------‖-‖--| - { Devonian ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { |-‖-‖-‖-‖-‖-‖-‖----‖------------------‖-‖--| - { Silurian ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { |-‖-‖-‖-‖-‖-‖-------------------------‖-‖--| - { Ordovician ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { |-‖-‖-‖-‖-‖-‖-------------------------‖----| - { Cambrian ...| ‖ ‖ ‖ ‖ ‖ ‖ ‖ | - { |-‖-‖-‖-‖-‖-‖-------------------------‖----| - { Etcheminian ...| ‖ ‖ ‖ ‖ ‖ ‖ | - |-‖-‖-‖-‖-----------------------------‖----| - Eozoic. | ‖ ‖ ‖ ‖ | - { Huronian ...| ‖ · | - { |-‖----------------------------------------| - { Laurentian. | ‖ | - { Grenvillian ...| ‖ | - { |------------------------------------------| - { Archæan ...| | - | | - +------------------------------------------+ - - -Note.--It is not supposed that the Geological Periods were of equal -lengths, as represented in the diagram. - - -ERRATA. - -Where _Cryptozoon prolificum_ occurs in the text, read _Cryptozoon -proliferum_. - -[Transcriber Note: Errata Corrections HAVE BEEN applied to text!] - - - - - I - - _THE CHAIN OF LIFE TRACED BACKWARD IN GEOLOGICAL TIME_ - -In infancy we have little conception of the perspective of time. To us -the objects around us and even our seniors in age seem to have always -been, and to have had no origin or childhood. It is only as we advance -in knowledge and experience that we learn to recognise distinctions -of age in beings older than ourselves. In thinking of this, it seems -at first sight an anomaly, or at least contrary to analogy, that the -oldest literature and philosophy deal so much with doctrines as to the -origins of things. In this respect primitive men do not seem to have -resembled children; and the fact that our own sacred records begin with -answers to such questions, and that these appear in the oldest literary -remains of so many ancient nations, and even in the folk-lore of -barbarous tribes, might be used as an additional argument in favour of -an early Divine revelation on such subjects, as a means of awakening -primitive men to the comprehension of their own place in the universe. - -However this may be, it is certain that modern science at first took a -different stand. - -The constancy of the motions of the heavenly bodies, our great -time-keepers, and of the changes on the earth depending upon them, and -the resolution of apparent perturbations into cycles of greater or less -length, impressed astronomers and physicists with the permanence of the -arrangements of the heavens and their eternal circling round without -any change. In like manner, on the rise of geology, the succession of -changes recorded in the earth seemed interminable, and Hutton could -say that in the geological chronology he could see "no vestige of a -beginning, no prospect of an end." - -But the progress of investigation has changed all this, and has brought -physical and natural science back to a position nearer to that of -the old cosmogonies. Physical astronomy has shown that the constant -emission of heat and light from the sun and other stars must have had -a beginning, and is hurrying on toward an end, that the earth and -its satellite the moon are receding from each other, and that even -the spinning of our globe on its axis is diminishing in rapidity. -In summing up these and other changes, Lord Kelvin says: "To hold -the doctrine of the eternity of the universe would be to maintain a -stupendous miracle, and one contrary to the fundamental laws of matter -and force." - -So, on our earth itself, we can now assign to their relative ages -those great mountain chains which have been emblems of eternity. We -can transfer ourselves in imagination back to a time when man and his -companion animals of to-day did not exist, when our continents and -seas had not assumed their present forms, and even when the earth was -an incandescent mass with all its volatile materials suspended in its -atmosphere. It is true that in all the changes which our earth has -undergone the same properties of matter and the same natural laws -have prevailed; but the interactions of these properties and laws -have been tending to continuous changes in definite directions, and -not infrequently to accumulations of tension leading to paroxysmal -vicissitudes. - -If all this is true of the earth itself, it is especially applicable -to its living inhabitants. Successive dynasties of animals and plants -have occupied the earth in the course of geological time; and as we go -back in the record of the rocks, first man himself and, in succession, -all the higher animals disappear, until at length in the oldest -fossiliferous beds only a portion of the more humble inhabitants of the -sea can be found. In the time of the formation of the oldest of these -rocks, or perhaps somewhat earlier, must have been the first beginning -of life on our planet. - -Just as we can trace every individual animal to a microscopic germ in -which all its parts were potentially present, so we can trace species, -genera, and larger groups of animals to their commencement at different -points of the earth's history, and can endeavour to follow the lines -of creation or descent back to the first beings in which vital powers -manifested themselves. All such beginnings must end in mystery, for -as yet we do not know how either a germ or a perfect animal could -originate from inanimate matter; but we may hope at least to make some -approximation to the date of the origin of life and to a knowledge of -the conditions under which it began to exist, confining ourselves for -the present principally to the Animal Kingdom. - -As preliminary to the consideration of this subject, we may shortly -notice the grades of animals at present existing, and then the evidence -which we have of their successive appearance in different periods of -geological time, in order that we may eliminate all those of more -recent origin, in so far as the knowledge at present available will -permit, and restrict our consideration to forms which seem to have been -the earliest. In attempting this, we may use for reference the table -of geological periods and animal types presented in the diagram facing -this chapter, which is based on one prepared by Prof. Charles A. White, -of the United States Geological Survey, with modifications to adapt it -to our present purpose. In this table the leading groups of animals are -represented by lines stretching downward in the geological column of -formations as far as they have yet been traced. Such a table, it must -be observed, is always liable to the possibility of one or more of its -lines being extended farther downward by new discoveries. - -The broadest general division of the Animal Kingdom is into back-boned -animals (Vertebrates) and those which have no back-bone or equivalent -structure (Invertebrates).[1] The former includes, besides man -himself, the familiar groups of Beasts, Birds, Reptiles, and Fishes. -The latter consists of the great swarms of creatures included under -the terms Insects, Crustaceans, Worms, Cuttle-fishes, Snails, Bivalve -Mollusks, Star-fishes, Sea-urchins, Coral Animals, Sea-jellies. -Sponges, and Animalcules. This mixed multitude of animals, mostly of -low grade and aquatic. Includes a vast variety of forms, which, though -comparatively little known to ordinary observers, are vastly numerous, -of great interest to naturalists, and, as we shall find, greatly older -in geological date than the higher animals. - -[Footnote 1: The twofold primary division now sometimes used, into -Metazoa and Protozoa, seems more arbitrary and unequal, and therefore -of less practical value.] - -It will be seen by a glance at the diagram that the higher vertebrates -are of most recent origin, man himself coming in as one of the newest -of all. Only the lower reptiles or batrachians and the fishes extend -very far back in geological time. None of the other vertebrate groups -reach, so far as yet known, farther back than the middle of the -geological scale--probably in point of time very much less than this. -Those of the invertebrates that breathe air reach no farther back than -the fishes, possibly not so far. On the other hand, all the leading -groups of marine invertebrates run without interruption back to the -Lower Cambrian, and some of them still farther. Thus it would appear -that for long ages before the introduction of land or air-breathing -animals of any kind, the sea swarmed with animal life, which was almost -as varied as that which now inhabits it. The reasons of this would seem -to be that the better support given by the water makes less demands -upon organs for mechanical strength, that the water preserves a more -uniform temperature than the air, and that arrangements for respiration -in water are less elaborate than those necessary in air. Hence the -conditions of life are, so to speak, easier in water than in air, more -especially for creatures of simple structure and low vital energy. -Besides this, the waters occupy two-thirds of the surface of the earth, -and in earlier periods probably covered a still greater area. - -We are now in a position to understand that the Animal Kingdom had -not one but many beginnings, its leading types arriving in succession -throughout geological time. Thus the special beginning of any one line -of life, or those of different lines, might form special subjects -of inquiry; but our present object is to inquire as to the first or -earliest introduction of life in our planet, and in what form or forms -it appeared. We may, therefore, neglect all the vertebrate animals and -the air-breathing invertebrates, and may restrict our inquiries to -marine invertebrates. - -In relation to these, six of the larger divisions or provinces of the -Animal Kingdom may suffice to include all the lower inhabitants of the -ocean, whether now or in some of the oldest fossiliferous rocks.[2] - -[Footnote 2: Some modern zoologists, having perhaps, like some of the -old Greeks, lost the idea of the unity of nature, or at least that of -one presiding divinity, prefer for the larger divisions of animals -the term _phylum_ or _phylon_, implying merely a stock, race or kind, -without reference to a definite place in an ordered kosmos.] - -Looking more in detail at our diagram, we observe that the higher -vertebrates nearest to man in structure extend back but a little -way, or, with a few minor exceptions, only as far as the beginning -of the Kainozoic or Tertiary Period, in the later part of which -we still exist. Other air-breathing vertebrates, the birds and -the true reptiles, extend considerably farther, to the beginning -of the previous or Mesozoic Period. The amphibians, or frog-like -reptiles, reach somewhat farther, and the fishes and the air-breathing -arthropods farther still. On the other hand, our six great groups of -marine invertebrates run back for a vast length of time, without any -companions, to the lowest Palæozoic, and this applies to their higher -types, the cuttles and their allies, and the crustaceans, as well as -to the lower tribes. Turning now again to our table, we find that -these creatures extend in unbroken lines back to the Lower Cambrian, -the oldest beds in which we find any considerable number of organic -remains, and leave all the other members of the Animal Kingdom far -behind. - -If now we endeavour to arrange the leading groups of these persistent -invertebrates under a few general names, we may use the following, -beginning with those highest in rank:-- - -(1) _Insects_ and _Crustaceans_ (Arthropoda). - -(2) _Cuttles, univalve and bivalve Shell-fishes_ (Mollusca). - -(3) _Worms_ (Annelida). - -(4) _Sea-urchins_ and _Sea-stars_ (Echinodermata). - -(5) _Coral Animals_, _Sea-anemones_, and _Sea-jellies_ (Cœlenterata). - -(6) _Sponges_, _Foraminifera_ and _Animalcules_ of simple organization -(Protozoa). - -There are, it is true, some animals allied to the mollusks and worms, -which might be entitled to form separate groups, though of minor -importance The position of the sponges is doubtful, and the great mass -of Protozoa may admit of subdivision; but for our present purpose these -six great groups or provinces of the Animal Kingdom may be held to -include all the humbler forms of aquatic life, and they keep company -with each other as far as the Early Cambrian. If, in accordance with -the previous statements, we choose to divide the earth's history by -the development of animal life rather than by rock formations, and to -regard each period as presided over by dominant animal forms, we shall -thus have an age of man, an age of mammals, an age of reptiles and -birds, an age of amphibians and fishes, and an age of crustaceans and -mollusks. - -It is only within recent years that the researches more especially of -Barrande, Hicks, Lapworth, Linarrson, Brögger, and others in Europe, -and of Matthew, Ford and Walcott in America, have enlarged the known -animals of the Lower Cambrian to nearly 200 species, and below this -we know as yet very little of animal life. We may therefore take the -Lower Cambrian, or "Olenellus Zone" as it has been called from one of -its more important crustaceans,[3] as our starting-point for plunging -into the depths below. In doing so, we may remark on the orderly and -symmetrical nature of the chain of life, and on the strange fact that -for so long ages animal life seems to have been confined to the waters, -and to have undergone little development toward its higher forms. It -is like a tree with a tall branchless stem bearing all its leaves and -verdure at the top, or like some obscure tribe of men long living in -isolation and unknown to fame, and then, under some hidden impulse -or opportunity, becoming a great conquering and dominant nation. Or -to compare it with higher things, it is like the Christian religion, -for ages confined to a small and comparatively unimportant people, -and developing slowly its faith and hopes, and then suddenly, under -the personal influence of Christ and His apostles, spreading itself -over the world, and in a few centuries becoming the ruling power in -its greatest empire, surviving the fall of this and permeating all -the great nations that sprang from its ruins. God's plans in nature, -in history, and in grace seem to us very slow in their growth and -maturity, but they are very sure. - -[Footnote 3: See figure, p. 20.] - - - - - _LIFE IN THE EARLY CAMBRIAN_ - - - - - II - - _LIFE IN THE EARLY CAMBRIAN_ - - -In the old Chaldean fable of the descent of Ishtar into Hades, to -recover her lost Tammuz, at each successive gate of the lower regions -she is stripped of some of her ornaments and garments, till at length -she has to appear naked and unadorned in the presence of the lord of -the Nether World. So in our descent from the surface on which men -live, through the successive rocky layers of the earth's crust, we -leave behind, one by one, all the higher forms of life with which we -are familiar; but there still remain to us our six groups of aquatic -invertebrates, in the guise, it is true, of species and genera now -unknown in a living state, yet well represented as far down as the -lower part of the Cambrian. Let us now suppose that we take our stand -on the shores of the Cambrian sea, or cast our dredge into its waters -in search of these old animals; though we can only actually do so by -painfully hammering and chiselling them out of their rocky tombs, and -this often in fragments which must be put together before we can fully -realize the forms and structures of the animals to which they belonged. - -We may pause here, however, to remark that neither the geographical -nor climatal conditions of the earth at this early time were similar -to these with which we are now familiar. The marine animals of the -Cambrian have left their remains in beds of sediment, which now -constitute rocks forming parts of our continents remote from the sea, -and much elevated above its level, showing that large areas, then under -the ocean, are now dry land; while there is no good evidence that -the sea and land have changed places. The facts rather indicate that -the continents have extended their area at the expense of the ocean, -which has, however, probably increased in depth. In evidence of these -statements, I need only mention that some of the oldest rocks in the -Scottish and Welsh hills, in Scandinavia, in Russia and in Bohemia, are -rich in Cambrian marine fossils. - -[Illustration: Fig. 1.--_Olenellus Thompsoni_, Hall. - -A characteristic Trilobite of the Lower Cambrian in North America. -After Walcott and specimen in Peter Redpath Museum.] - -In America, in like manner, such rocks are found on the flanks of the -Appalachians, in New Brunswick, and in Newfoundland, in the table-land -of Colorado and in the Rocky Mountains. In point of fact, a map of -the Northern Hemisphere at this period would show only a limited -circumpolar continent with some outlying islands to the south of it, -and shallows stretching across the northern part of the areas of the -present Atlantic and Pacific Oceans. The great ocean, however, thus -extending over most of the temperate and tropical parts of the Northern -Hemisphere, was probably also more muddy and shallow than that of -modern times. The surface temperature of this vast ocean was also, -it is probable, more uniform than that of the modern sea, while even -its profounder depths or abysses would have more earth-heat than at -present. Thus we may, without hesitation, affirm that in this early -age the conditions for the introduction of swarming marine life of low -grade, and its extension over the whole earth, were at a maximum. - -Let us inquire, then, what these old Cambrian seas actually produced, -more especially in the early portions of that ancient and probably -protracted time. - -The most highly organized type of which we have any certain evidence -is that of the Crustacea, the group to which our modern lobsters and -crabs belong, and its most prominent representatives are the trilobites -(Figs. 1, 2), so called from the three lobes into which the body is -divided. These creatures are indeed remarkable for the twofold property -of bilateral symmetry, and fore and aft jointed structure, both based -on the number three. From front to rear we have a large head, usually -with well-developed eyes and oral organs, a middle or thoracic part -composed of a series of movable segments, and a tail-piece sometimes -small, sometimes nearly as large as the head. Transversely, the body -is divided into a central and two lateral lobes, which can be seen in -the head, the thorax, and usually in the tail as well. The organization -of these animals must have been as complex as that of most existing -Crustaceans. Their nerve system must have been well developed; a vast -number of muscles were required to move the different parts of the -trunk, and the numerous and complex limbs which have been observed -in some of the species, and no doubt were possessed by all. Their -digestive and circulatory organs must have been in proportion to the -complexity of their locomotive organs. - -[Illustration: Fig. 2.--_Triarthrus Becki_, Green. - -A Trilobite of primitive type, showing its limbs and antennæ. (After -Beecher.)] - -Figure 2, borrowed from Beecher,[4] shows the limbs of a species, -not of the Lower Cambrian, but of a somewhat later formation. There -can be no doubt, however, that those of earlier species were equally -perfect, more especially as Triarthrus is an animal of an old type -approaching to extinction in the age succeeding the Cambrian, and its -representatives in the earlier and palmy days of the family could not -have been inferior in organization. These creatures swarmed in every -sea in the Cambrian period, and were represented by a great number of -species, some of them of large size, others very small; some -many-jointed, others few-jointed, and with a great variety of tubercles, -spines, and other ornamental and protective parts. If we ask for their -affinities and place in the great group of Crustacea, the answer must -be that, while in some points allied to the higher forms, they approach -most nearly to those which occupy a medium position in the class, and -are, in fact, a composite type, presenting points of structure now -distributed among different groups. If we ask for affinities with lower -groups, we have to reply that their nearest allies in this direction -are the bristle-footed marine worms; but there is a vast gap, both -in the Cambrian and Modern seas, between any of these worms and the -Crustacea, which, either as embryos or as adults, have any resemblance -to them. - -[Footnote 4: _American Journal of Science_, 1896.] - -The Trilobites, after appearing in a great variety of generic and -specific forms, and playing a most important part in their time, -were not destined to continue beyond the Carboniferous period, and -before that time they were beginning to give place to the Limuli, -King-crabs, or Horseshoe-crabs, a few species of which continue on our -coasts until the present time. In this limited duration the Trilobites -present a strange contrast to certain shrimp-like Crustaceans, their -contemporaries (the Phyllopods), which very closely resemble some -still extant, and the same remark applies to swarms of little bivalve -Crustaceans (Ostracods), which are still represented by hosts of modern -species both in the sea and in the fresh waters. There is, however, -a remarkable group of shrimp-like Crustaceans, represented in the -modern world by only a few small species, which in the Cambrian age -attained greater size, and constitute a very generalized type combining -characters now found in lower and higher groups of Crustacea. - -_Hymenocaris vermicauda_ of Salter (Fig. 3) may serve to illustrate one -of these primitive forms. - -[Illustration: Fig. 3.--_Hymenocaris vermicauda_, Salter. - -A Lower Cambrian Shrimp of generalized type. (After Salter.)] - -In point of fact, as Dr. Henry Woodward has shown in an able -presidential address delivered to the Geological Society in 1895, at -the base of the Lower Cambrian we still have several distinct groups -of Crustacea; and if with some we were to hold them as traceable to -one original form or to a worm-like ancestor, we must seek for this -far back in those pre-Cambrian rocks in which we find no Crustaceans -whatever. There is, it is true, no good reason to demand this; for -whatever the cause, secondary or final, which produced any form of -Crustacean in the Lower Cambrian, it might just as well have produced -several distinct forms. Evolutionists seem to be somewhat unreasonable -in demands of this kind, for any cause capable of originating a new -form of living being, might have been operative at the same time in -different localities and under somewhat diverse conditions, and may -also have acted at different times. All imaginary lines of descent of -animals are more or less subject to this contingency; and this may -partly account for the great diversity in the lines of affiliation -presented to us by evolutionists, which may in part have a basis in -fact in so far as distinct varietal and racial forms are concerned, but -may just as likely be entirely fallacious in the case of true species. -In any case, in the lowest rocks into which we can trace Crustacea, we -have already probably five of the orders into which their successors -in the modern seas are divided by zoologists; and this is certainly a -singular and suggestive fact, the significance of which we shall be -better prepared to understand at a later stage of our investigation. - -Allied in some respects to the Crustacea, though much lower in grade, -are the marine Worms--a great and varied host--usually inhabiting the -shallower parts of the ocean; though the 330 species collected by the -_Challenger_ expedition show that they also abound in those greater -depths to which voyagers have only recently had access. Sea-worms seem -thus to be able to live in all depths, as well as in all climates; and -in accordance with this they abound in the oldest rocks, which are -often riddled with the holes caused by their burrowing, or abundantly -marked on the surfaces of the beds with their trails. - -The great province of the Mollusca, in which, for our present purpose, -we may include some aberrant and rudimentary Molluscoids, is now best -known to us by its medium types, the univalve and bivalve Shell-fishes; -the higher group of the Cuttle-fishes and Nautili, though not uncommon, -being much less numerous, and one at least of the lower groups, the -Lamp-shells or Brachiopods, being represented in the modern world -by but few forms. The extension of the Mollusks backwards into the -Cambrian is remarkable as being on the whole meagre in comparison with -that of the Crustaceans, and as presenting only in small numbers the -types most common in later times. One or two shells, and perhaps some -tracks, represent the highest group: some forms resembling the floating -species of Sea-snails, and a very few ordinary bivalves represent -the types best known in the modern seas; while the Brachiopods, and -probably some still simpler forms, are in great comparative excess. -The individual specimens are also of small size, as if these creatures -were but insinuating themselves on the arena of life in insignificant -and humble forms. So far as yet known, the lowest groups supposed -to be allied to the Mollusks, the Ascidians or Sea-squirts, and the -Sea-mosses (Polyzoa), do not appear; but they may have been represented -by species which possessed no hard parts capable of preservation. - -This leads us to the consideration that while all the Crustacea -necessarily possess some kind of crust or external skeleton, the -Mollusks are very different in this respect. While some of them have -ponderous shells, others even of the highest forms are quite destitute -of such protective parts. This again leads to a curious question -respecting the armature of the Trilobites. Some of these, even of the -larger species, have strong and formidable spines, like those of the -King-crabs and other modern Crustaceans. Now in the modern species we -know these organs to be intended to defend their possessors against the -attacks of fishes more swift and powerful than themselves. But what -enemies of this kind had the Trilobites to dread? Yet species a foot or -more in length presented great bayonet-like spines. - -[Illustration: Fig. 4.--_Ctenichnites ingens_, Matthew. - -A slab with markings of aquatic animals. From specimen in Peter Redpath -Museum.] - -All that we know on this subject is that on the surfaces of the Lower -Cambrian rocks there are in some places complicated and mysterious -tracks or scratches, which seem to have been produced when the rock -was in the state of soft mud, by large and swiftly swimming animals -possessing some sort of arms or similar appendages (Fig. 4). Matthew -has ingeniously suggested that they may have been large Mollusks allied -to the modern gigantic Squids which still abound in the ocean, that -they may have been sufficiently powerful to prey on the Trilobites, -and, being swift swimmers, would have found them a helpless prey but -for their defensive spines. Yet such large Mollusks might have perished -without leaving any remains recognisable in the rocks, except what -may be termed their hand-writing on clay. A few small examples of the -shell-bearing species of these highest Mollusks, however, appear in -the Cambrian, and in the succeeding ages they become very abundant and -attain to large dimensions, again dwindling toward modern times. It -would thus seem that for some unknown reason the highest and lowest -Mollusks may have been locally plentiful, but the intermediate types -were rare. - -The much lower group of Echinoderms, or Sea-urchins and Sea-stars, -curiously enough puts in but a small appearance in the Early Cambrian, -being represented, as far as yet known, by only one embryonic group, -the Cystideans. A little later, however, Feather-stars became greatly -abundant, and a little later still the true Star-fishes and Urchins. -The aberrant group of the Sea-slugs seems, so far as known, to be of -more modern origin; but most of these animals are soft-bodied, and -little likely to have been preserved. - -The great group of the coral animals, so marked a feature of later -ages, is scarcely known in the oldest Cambrian, except by some -highly generalized forms[5] (Fig. 5). There are, however, small -Zoophytes referable to the lower type of Hydroids, and markings which -are supposed to be casts of stranded Jelly-fishes. If, with some -naturalists, we regard the Sponges as very humble members of the -coral group (Cœlenterata), then we have a right to add them to its -representatives in the lowest Cambrian; but perhaps they had better be -ranked with the next and lowest group of all--the Protozoa. - -[Footnote 5: Dr. G. J. Hinde has carefully studied these forms, and -also similar species occurring in Lower Cambrian beds in different -parts of North America, Spain, Sardinia, and elsewhere. See note in the -Appendix, and _Journal Geol. Society of London_, vol. xlv. p. 125.] - -[Illustration: Fig. 5.--_Archæocyathus profundus_, Billings. - -Possibly a Coral of generalized type from the Lower Cambrian of L'Anse -à Loup, Labrador. A small specimen.] - -[Illustration: Fig. 6.--_Structures of A. profundus (magnified)._ - -From specimens in Peter Redpath Museum. - -(_a_) Lower acervuline portion. (_b_) Upper part, with three of the -radiating laminæ and section of pores, (_c_) Portion of lamina, with -pores, the calcareous skeleton unshaded.] - -These are the humblest of all the inhabitants of the sea, presenting -very simple, jelly-like bodies with few organs, but sometimes producing -complex and beautiful calcareous and siliceous coverings or tests. -Animals of this type have been found in the Lower Cambrian, though not -in such vast multitudes as in some later formations. There are also in -the Cambrian some large, laminated, calcareous bodies (Cryptozoon of -Hall), to be noticed more fully below, and which have recently been -traced in still lower deposits even below the lowest Cambrian (Figs. -7, 8). These have some resemblance to the layer-corals or stromatoporæ -of the Silurian and Ordovician, which are by many regarded as the -skeletons of coral animals of a low type; but the microscopic structure -of Cryptozoon rather allies it with some of the larger forms of -Protozoa found higher up in the series of formations. We shall have to -discuss this later in connection with still older fossils. - -[Illustration: Fig. 7.--_Cryptozoon proliferum_, Hall. - -Portion of slab reduced in size. (After Hall.) See also Fig. 59, p. -237.] - -[Illustration: Fig. 7_a_.--_Portion of thin section of Cryptozoon -proliferum (magnified × 50)._] - -(_a_) Corneous layers, (_a¹_) One of these dividing, (_b_) Intermediate -stroma with granules of calcite, dolomite and quartz, traversed by -canals. - -_From a Micro-photograph by_ Prof. Penhallow. - -[_To face p. 39._ - -If now in imagination we cast our tow-net or dredge into the sea of the -Lower Cambrian, we may hope to take specimens illustrative of all our -six groups of invertebrate animals, and under several of them examples -of more than one subordinate group. Of the Crustaceans we might have -representatives of four or five ordinal groups, and of the Mollusca -as many. These are the two highest and most complicated. In the four -lower groups we would naturally have less variety, though it would seem -strange, were it not for so many examples in later periods, that the -dominant and highest groups should be most developed in regard to the -number of their modifications. - -[Illustration: Fig. 8.--_Diagrammatic section of two Laminæ of -Cryptozoon, showing the Canals of the intermediate space, or Stroma -(magnified)._ - -Specimen in Peter Redpath Museum.] - -Of the whole we might perhaps have been able to secure at least 200 -species even in one locality. The likelihood is that if there had been -a collecting expedition like that of the _Challenger_ in Early Cambrian -times, it could have secured thousands of specific forms representing -all the above types, more especially as we probably know very little of -the softer and shell-less animals of these old seas, and there is some -reason to believe that these may have been in greater proportion than -in the present ocean. - -In illustration of the richness of some parts of the lowest Cambrian -sea, I may refer here to the large and beautifully illustrated Memoir -of Walcott on the Lower Cambrian, containing fifty folio plates of -species collected in a few districts of North America; and, as a minor -example, to the contents of a loose boulder of limestone of that age, -found at Little Metis on the Lower St. Lawrence, under the following -circumstances (Fig. 9):-- - -[Illustration: Fig. 9.--_Lower Cambrian Fossils found in a few cubic -inches of limestone in a conglomerate at Little Metis; viz., Trilobites -of genera Olenellus, Ptychoparia, Solenopleura, Protypus; Brachiopod -of genus Iphidea; Pteropod of genus Hyolithes; Gastropod, genus -Stenotheca; Sponge, undetermined._] - -Along what is now the valley of the Lower St. Lawrence and the gulf -of the same name, there seem to have been deposited in the oldest -Cambrian or Olenellus period beds of limestone rich in shells of marine -animals and fragments of these. These can be seen in place in some -parts of Newfoundland, and here and there on the hills bounding the -St Lawrence River; but for the most part they have been swept away -by the sea when these districts were being elevated to form parts -of the American land. Their ruins appear as boulders and pebbles in -thick beds of conglomerate or pudding-stone, constituting portions of -the Upper Cambrian and Lower Ordovician series, which now occupy the -south coast of the Lower St. Lawrence. In one of these boulders, less -than a foot in diameter, removed from its hard matrix and carefully -broken up, I found fragments representing eleven different species, -of which no less than eight were trilobites, one a gastropod, one a -brachiopod, and one probably a sponge--and this forms an interesting -illustration of the number of species sometimes to be found in a -limited space, and also of the great prevalence of the Trilobites in -these beds. The statistics of these groups for North America, as given -by Walcott, show 165 species belonging to all the groups enumerated -above, and of these the Trilobita constitute one-third of the whole; -so that the Olenellus Zone, as it has been called from one genus of -these Crustaceans, might well be named the reign of Trilobites, unless, -indeed, as the indications already referred to seem to show, giant -cuttle-fishes, destitute of shells, were then the tyrants of the sea, -but are represented only by the markings of their long and muscular -arms on the soft sea mud while dashing after their Crustacean prey. -What I desire, however, chiefly to emphasize is, that in the lowest -beds of the Cambrian we have evidence of sea-bottoms swarming with -representatives of all the leading types of marine invertebrate life, -and therefore seem to be still far from the beginning of living things, -if that was a slow and gradual process, rather than a sudden or rapid -series of events. - - - - - _PRE-CAMBRIAN LIFE_ - - - - - III - - _PRE-CAMBRIAN LIFE_ - - -Having traced the chain of life through the long geological ages, from -the present day back to the Cambrian Period, we may now take our stand -on the fauna of the lowest Cambrian or Olenellus Zone, as a platform -whence we may dive into still deeper abysses of past time. Here, -however, we seem to have arrived at a limit beyond which few remains -of living things have yet been discovered, though there still remain -pre-Cambrian deposits of vast thickness and occupying large areas of -our continents. These pre-Cambrian formations are as yet among those -least known to geologists. The absence of fossils, the disturbances and -alterations which the rocks themselves have undergone, and which make -their relative ages and arrangement difficult to unravel, have acted -as deterrents to amateur geologists, and have to some extent baffled -the efforts of official explorers. In addition to this, workers in -different regions have adopted different methods of arrangement and -nomenclature; and in a very recent address, the Director-General of the -Geological Survey of Great Britain expresses his inability to satisfy -himself of the equivalency of the different pre-Cambrian groups on the -opposite sides of the Atlantic, and in consequence prefers to retain -for those of Britain merely local names. - -On the other hand, those who hold the modern theories of gradual -evolution repudiate the idea that the Lower Cambrian fauna can be -primitive, and demand a vast series of changes in previous time to -prepare the way for it. In any case this comparatively unexplored -portion of geological time holds out the inducement of mystery and the -possibility of great discoveries to the hardy adventurers who may enter -into it. It must now be our effort to explore this dim and mysterious -dawn of life, and to ascertain what forms, if any, are visible amid its -fogs and mists. - - -The Kewenian or Etcheminian. - -In certain basal Cambrian or infra-Cambrian beds, found by Matthew in -Southern New Brunswick, by Walcott in Colorado, and by Scandinavian -and English geologists in their respective countries, we find a -few remains referred to Algæ, or seaweeds; small tests or shells of -Protozoa; burrows and trails similar to those of modern sea-worms; -a few bivalve shells allied to modern Lingulæ, but presenting some -remarkable generalized characters; some bivalve and shrimp-like -Crustaceans, spicules of sponges, and large laminated forms -(Cryptozoon) similar to those already referred to as occurring in the -Upper Cambrian; also certain mysterious markings that are supposed to -have been produced by the arms or tentacles of free-swimming animals -of various kinds. In these lower beds the Trilobites have nearly or -quite disappeared, being represented only by doubtful fragments. The -beds of rock, originally sandy or muddy sediments, contain fossils very -sparingly, and only in certain layers separated by great thicknesses -of barren material, as if earthy matters were being deposited very -rapidly, or as if animal life was rare on the sea-bottom except at -intervals. It has, however, been suggested as possible[6] that much -of the marine population in those early times consisted of pelagic or -swimming animals destitute of any hard parts that could be preserved. -In addition to biological arguments in favour of this view, there is -the fact that some of the beds are stained with carbonaceous or coaly -matter, as if the sediment had been mixed with decomposed remains of -plants or animals retaining no determinate forms. Future discoveries -may increase our knowledge of the life of this period preceding the -Cambrian, but it is evident that so far as these rocks have been -examined, they indicate a great step downward in regard to the variety -and complexity of marine life. - -[Footnote 6: By Prof. Brookes, of Johns Hopkins University.] - -Still we must bear in mind that in later periods there have been times -of rapid deposition, in which, in certain localities at least, great -thicknesses of rock with few organic remains were formed. We have -instances of this in the later Cambrian, in the Ordovician, and still -later in the Permian and Trias. Thus in the beds immediately underlying -the lowest Cambrian we may be passing through a tract of comparative -barrenness to find more fertile ground below. - -It is also to be observed that there is evidence of disturbance -occurring in the interval between the lowest Cambrian and the highest -pre-Cambrian, which may involve the lapse of much time not recorded in -the localities hitherto explored, but of which monuments may be found -elsewhere. - -We may now, taking some North American localities as our best available -guides, inquire as to the nature and contents of the beds next below -the Lower Cambrian. - -[Illustration: Fig. 10.--_Section at Hanford Brook._ (After Matthew.) - -Showing St. John group resting on Etcheminian, and this on Coldbrook -(Huronian).] - -In Southern New Brunswick, Matthew indicated, several years ago, the -occurrence of certain conglomerates and sandy and slaty beds over the -rocks, mostly of igneous origin, constituting a great thickness of -beds under the Cambrian, and known locally as the "Coldbrook" series, -which is probably equivalent to the Huronian of Northern and Western -Canada, to be noticed later. These beds were at first regarded as an -upper member of the Huronian, but subsequently it was thought better -to unite them with the overlying Cambrian as basal Cambrian. The fact -that these problematical beds were ascertained to be unconformable to -the Cambrian, and the peculiarity of their fossils, led to their being -constituted a separate group under the name _Etcheminian_, which seems -to represent a time and conditions introductory to the Cambrian (Fig. -10). The fossils in these beds are few and hard to find. Matthew has -kindly furnished me with the following list.[7] The Trilobites are -conspicuous by their absence. Sea-worms have left burrows, trails, and -casts, which probably represent several species (Fig. 11). A single -little shell (Volborthella) is supposed to be a precursor of the -straight chambered shells allied to the modern nautilus, which become -so large and numerous in succeeding periods. There are a few univalve -shell-fishes allied to modern sea-snails, a brachiopod of the antique -genus Obolus, some fragments supposed to represent Cystideans, a -rudimentary type of the stalked sea-stars so abundant later, spicules -of sponges and minute Protozoa, with shells not unlike those of their -modern successors. This meagre list sums up the forms of life known -in the Etcheminian of this district, one in which the Cambrian beds -exhibit the rich and varied fauna of Trilobites and other animals -described and figured by Matthew in several successive volumes of the -"Transactions of the Royal Society of Canada" (Fig. 12). - -[Footnote 7: "Transactions Royal Society of Canada," vol. vii.] - -[Illustration: Fig. 11.--_Trails of Worms of two types (Psammchnites -and Planilites)._] - -Beds in Newfoundland (the Signal Hill and Random Sound series), -underlying the Lower Cambrian, have afforded to Murray and Billings -some well-characterized worm-castings of spiral form, and a few -problematical forms known as Aspidella, which may be Crustaceans or -Mollusks allied to the limpets (Fig. 13). - -[Illustration: Fig. 12.--_Group of pre-Cambrian (Etcheminian) Animals -from the Etcheminian._ (After Matthew.)] - -The name "Etcheminian" is derived from that of an ancient Indian tribe -of New Brunswick. - -(_a_) Volborthella, supposed to be a Cephalopod shell. (_b_) -Pelagiella. (_c_) Orthotheca, supposed to be Pteropods. (_d_) Primitia, -an Ostracod Crustacean, (_e_) Obolus, a Brachiopod shell. (_f_) -Platysolenites, probably fragment of a Cystidean. (_g_) Globigerinæ, -casts of Foraminiferal shells, Etcheminian, New Brunswick. - -[Illustration: Fig. 13.--_Arenicolites (Spiroscolex) spirales_ -(Billings) _and Aspidella tenanovica_ (Billings), _Signal Hill Series, -Newfoundland._] - -[Illustration: Fig. 14.--_Fragment of Cryptozoon, Grand Cañon, Arizona._ - -Photograph from a specimen presented by Dr Walcott to the Peter Redpath -Museum.] - -In a thick series of pre-Cambrian beds in the Colorado Cañon in the -Western United States, Walcott has found a small roundish shell of -uncertain affinities,[8] a species of Hyolithes, probably a swimming -sea-snail or Pteropod, a small fragment which may possibly have -belonged to a Trilobite, and some laminated forms which, if organic, -are related to the Cryptozoon already mentioned (Fig. 14). - -[Footnote 8: Discinoid or Patelloid.] - -The Kewenian series of Lake Superior has yielded no fossils, but the -pipestone beds of Minnesota, supposed to be about the same age, have -afforded a small bivalve shell allied to Lingula;[9] and the black -shales of the head of Lake Superior contain some impressions supposed -to be trails of animals.[10] - -[Footnote 9: Winchell.] - -[Footnote 10: Selwyn and Matthew.] - -It has been a question whether the beds above referred to should be -regarded as a downward continuation of the Cambrian, or as the upper -part of an older system. Matthew, whose opinion on such a subject is -of the highest authority, regards them as a distinct system, but as -belonging, with the Cambrian, to the great Palæozoic Period. Van -Hise, and some other United States authorities, would separate them -even from the Palæozoic, and unite them with the underlying Huronian, -as representing a "Proterozoic" or "Algonkian" Period. This is merely -a matter of classification, necessarily more or less arbitrary; but I -believe the facts to be stated subsequently show that it will be best -to unite the Etcheminian and its equivalents with the Palæozoic, and to -place the groups lower than this in one great division, equivalent to -Palæozoic, and for which many years ago I proposed the name "Eozoic," -or that of the Dawn of Life. - -Having thus hastily glanced at the slender fauna of the rocks -immediately below the Cambrian, we may now proceed to inquire a little -more in detail into its true value and import as leading toward the -beginning of life. I have already referred to the apparently sudden -drop in the number of groups and of species below the base of the -Cambrian, and have hinted that this may be an effect of temporary -local conditions of deposit or of defective information. Another fact -that strikes us is the diverse and miscellaneous character of the -fossils that remain to us; and this would suggest that we are either -dealing with a mere handful picked at random, as it were out of a -richer fauna, or that in the beginning of things the gaps and missing -links between different forms of life were even more pronounced than -at present. This, however, would be likely to occur if the plan of -creation was to represent at first different types, with few forms in -each; to produce, in short, a sort of type collection representing the -whole range of organization by a few characteristic things rather than -to give a complete series, with all the intermediate connections. Such -a mode of introduction of life is not _à priori_ improbable, however at -variance with some prevalent hypotheses. - -Beginning with the higher Invertebrates, we must not conclude that -we have altogether lost the Trilobites. The fragments referred to -this group may represent at least a few species, and it would be very -interesting to know more of these as to their relations to their -successors, and whether they are tending to lower or more embryonic -forms. The bivalve Crustaceans (Ostracods) may be regarded as inferior -in rank to the Trilobites, but are still very complex, and specialized -animals and a specimen silicified in such a manner as to show the -interior organs testified that, as far back as the Carboniferous at -least, these creatures were as highly organized as at present,[11] -while their generally larger size in the earlier formations tends to -show that they have rather been degenerating in the lapse of geological -time. - -[Footnote 11: _Palæocypris Edwardsi_, Brougniart, Coal Formation of St. -Etienne, France.] - -In regard to the Sea-worms, the burrows, castings, and trails found -in the pre-Cambrian beds are scarcely, if at all, different from -those now seen on sandy and muddy shores, and would seem to indicate -that these highly organized and very sensitive and active creatures -swarmed in the muddy bottom of the pre-Cambrian Sea, and lived in the -same way as at present. It is impossible, however, to know anything -of the internal structures of these creatures, but the marks left by -their bristle-bearing feet seem to indicate that some of them at least -belong to the higher group of Sea-centipedes, creatures rivalling the -Crustaceans in complexity of organization, and near to them in plan -of structure, though at present usually widely separated from them in -current systems of classification. In the Ordovician system, next above -the Cambrian, Hinde has found many curiously formed jaws of animals of -this kind, which show at least that their alimentary arrangements were -similar to those now in force. If any of the problematical "Conodonts" -discovered by Pander in the Cambrian of Russia belonged to marine -worms, this inference would be extended back to the Lower Cambrian, -so that if the evidence of structure anywhere remains we may hope -to find that the pre-Cambrian worms were not inferior to their more -modern successors, perhaps even that in this early period, when they -probably played a more important part in nature, they were of higher -organization than in later times. - -The evidence as to pre-Cambrian mollusks, so far as it goes, is -even more curious. The little shell called Volborthella, so far as -can be judged from its form and internal structure, is a miniature -representative of these straight Nautili, the Orthoceratites of -the Ordovician and later Palæozoic rocks; and no one doubts that -these latter belong to the highest class of the Mollusks, a class -approaching in the development of nerve system and sensory organs to -the Vertebrates themselves. This tiny member of the great class of -Cuttle-fishes may perhaps have been more nearly allied to the modern -Spirula than to the Nautilus. In any case, if, as seems altogether -probable it was, a mollusk, it must have been one of advanced type, and -with a highly complex structure, as well as the singular apparatus for -flotation implied in a chambered shell with a siphuncle. - -Next to this among these primitive Mollusks are straight and spiral -shells representing those delicate and beautiful animals of the modern -seas, the Pteropods, or wing-footed Sea-snails, beautiful and graceful -creatures, the butterflies of the sea, and moving in the water with -the greatest ease and beauty by the aid of membranous fins, or wings, -sometimes brightly coloured. These creatures abound in all latitudes -in the modern ocean, and their delicate shells sometimes accumulate in -beds of "Pteropod sand." They very early entered on the arena of marine -life, and have continued to this day. - -We miss here the two great Molluscan groups of the creeping Sea-snails -like the limpet and whelk, and of the ordinary bivalves like the -oyster and cockle. Both are present in the lowest Cambrian, though in -small numbers compared with their present abundance. Possibly they had -not yet appeared in the Etcheminian Sea, though the muddy and sandy -bottoms, evidenced by its slates and sandstones, would seem to have -afforded favourable habitats, and warrant the expectation that species -may yet be found. - -The case was different with the little group of the Lamp-shells, or -Brachiopods. These creatures, somewhat resembling the ordinary bivalves -in their shelly coverings, were very dissimilar in their internal -structure, and once settled on the bottom they were attached for life, -not having even the limited means of locomotion possessed by the -Sea-snails and common bivalves. They collected their food wholly by -means of currents of water produced by cilia, or movable threads, on -arms or processes within their shells. In this they resembled the young -or embryo stages of some of the more ordinary Mollusks, though they are -so remote from these in their adult condition that they have usually -been placed in a distinct class, and some naturalists have thought -it best to separate them from the Mollusks altogether. Their history -is peculiar. Coming into existence at a very early date, they became -very abundant in early Palæozoic times, then gradually gave place to -the ordinary bivalves, and in the modern seas are represented by very -few species. Yet while in the middle period of their history they are -represented by very many peculiar specific and generic forms. Some of -the earliest types, like Obolus and Lingula, persist very long, and -the latter has continued without change from the Early Cambrian to the -Modern period. - -The great group of the Sea-stars and Sea-urchins appears only in a -few of its lower forms, and seems to be the only class represented by -embryonic types. The coral animals are absent, so far as known. The -Jelly-fishes and their allies cannot be preserved as fossils, but some -peculiar markings, at one time regarded as plants, are now supposed to -be trails made by the tentacles of creatures of this kind moving over -muddy bottoms. A few spicules indicate Sponges, and the ubiquitous -groups of the marine Protozoa, the Foraminifera and the Radiolaunus, -are represented by shells scarcely distinguishable from those of modern -species. The great and peculiar forms represented at this early time by -Cryptozoon and its allies seem long ago to have perished, and we shall -have to return to them in a later stage of our inquiry. - -To sum up the little that we know of this earliest Palæozoic life:--It -was perfect of its kind, equally pregnant with evidences of design, and -of the nicest and most delicate contrivance as the animal life of any -later time, and it presupposed vegetable life and multitudes of minute -organic beings altogether unknown to us to nourish the creatures we do -know. As an example of this, a little Brachiopod or sponge nourished -by the currents produced by its cilia, or a Jelly-fish gathering -food by its thread-like tentacles, or a Globigerina selecting its -nourishment by its delicate gelatinous pseudopods, required an ocean -swarming with minute forms of life, which probably can never be known -to us, but every one of which must have been an inscrutable miracle of -organization and vital function. - -Lastly, with reference to our present subject, the Etcheminian fossils -carry life backward one whole great period earlier than the Lower -Cambrian, and appear to indicate that we are approaching a beginning -of living things in the Palæozoic world. Much no doubt remains to be -discovered, but it would seem that any future discoveries must fail to -negative this conclusion. - - -The Huronian. - -In whatever way the rocks immediately below the Cambrian may be -classified, it is certain that the next system in descending order -is that to which Logan long ago gave the name Huronian, from its -development on Lake Huron[12]--a name to which it is still entitled, -though there may, perhaps, be some grounds for dividing it into an -upper and lower member.[13] To this sub-division, however, we need -not for the present give any special attention. In the typical area -of Lake Huron the Huronian consists of quartzites, which are merely -hardened sandstones, of slates which are muddy or volcanic-ash beds, -of conglomerates or pebble-rocks, and of coarse earthy limestone. -With these rocks are deposits of igneous material which represent -contemporary volcanic eruptions. In other districts, as in New -Brunswick, Newfoundland, etc., the beds have been considerably altered, -and are locally more mixed with igneous products. The physical picture -presented to us by the Huronian is that of a shore deposit, formed -under circumstances in which beds of pebbles and sand were intermixed -with the products of neighbouring volcanoes. - -[Footnote 12: Dr. G. M. Dawson, F.R.S., the present Director of the -Geological Survey of Canada, whose judgment in this matter should be of -the highest value, holds that the original simple arrangement of Logan -still holds, notwithstanding the multitude of new names proposed by the -Western Geologists of the United States.] - -[Footnote 13: Van Hise, "Pre-Cambrian Rocks of North America." _Comptes -Rendus_, 5th Session International Geol. Congress 1891, p. 134. Also -"Report U.S. Geol. Survey, 1895."] - -[Illustration: Fig. 15.--_Annelid Burrows, Hastings Series, Madoc._ - -1. _Transverse section of Worm-burrow_--magnified, as a transparent -object. (_a_) Calcareo-silicious rock. (_b_) Space filled with -calcareous spar, (_c_) Sand agglutinated and stained black. (_d_) Sand -less agglutinated and uncoloured. 2. Transverse section of Worm-burrow -on weathered surface, natural size. 3. The same, magnified.] - -Such a formation is not likely to afford fossils in any considerable -number and variety, even if deposited at a time of abundant marine -life. It is therefore not wonderful that we find little evidence of -living beings in the Huronian. In Canada I can point to nothing of this -kind, except a few cylindrical burrows, probably of worms (Fig. 15), -and spicules possibly of silicious sponges, which occur in nodules of -chert in the limestones, traces of laminated forms like Cryptozoon -or Eozoon (Fig. 17), and minute carbonaceous fragments which may be -debris of sea-weeds or Zoophytes. In rocks of similar age in the United -States, Gresley has recently discovered worm-burrows, and in Brittany -there are quartzite beds in which Barrois and Cayeux believe that they -have found tests of Radiolarians, Foraminifera and spicules of sponges, -but their organic nature has been denied by Rauff, of Bonn. The casts -of Foraminifera, however, at least appear to be organic (Fig. 16), and -it is quite likely that Cayeux may be able to verify his Radiolarians -and sponges as well. Matthew's observations in New Brunswick in any -case establish their probability. Gümbel also recognises a species of -Eozoon in the equivalent rocks of Bavaria (see p. 213). - -[Illustration: Fig. 16.--_Casts of Foraminifera, from the Huronian of -Brittany._ (After Cayeux.) - -Compare with Globigerinæ on Fig. 12 and Archæospherinæ, Figs. 50-54.] - -[Illustration: Fig. 17.--_Cryptozoon or Eozoon from the Hastings -Series, Tudor, Ontario_ (natural size). - -From a specimen collected by the late Mr. Vennor, and now in the -collection of the Geological Survey, Ottawa. (See also Frontispiece and -figure of _Eozoon Bavaricum_, p. 213.)] - -It is evident that here we have approached the limit of the higher -forms of marine invertebrate life, having as yet nothing to show except -worms and Protozoa. It is to be observed, however, that there may be -somewhere Huronian deposits formed in deep and quiet waters, which may -give better results, and that the unconformity between the Huronian and -overlying Kewenian may indicate a lapse of time, of which monuments may -yet be found. - - -The Laurentian. - -Last of all we have the widely distributed Laurentian system of -Logan, the oldest known to geologists, and which with the Huronian -constitutes the great Archæan group of formations of Dana and others. -In its lowest part this consists entirely of the stratified granitic -rock known as gneiss, inter-bedded in some places with dark-coloured -crystalline rocks or schists. This may be a part of the first-formed -crust of our globe, produced under conditions different from those -of any later rocks, and incompatible with the existence of life. The -upper part of the Laurentian system, however, known in Canada as the -"Grenville Series," shows evidence of ordinary marine deposition in -quiet waters, which may have been not unfavourable to the lower forms -of marine life; and though its beds have been greatly changed by heat -and pressure, we can still to some extent realize the conditions of a -time of comparative quiescence intervening between the underlying Lower -Laurentian and the succeeding Huronian. This part of the system still -contains gneisses, bedded diorites, and other rocks which may have been -volcanic; but it has also quartzites and quartzose gneisses which must -have been sandstones or shales, thick limestones, beds of carbon now -in the state of graphite or plumbago, and large beds of iron ore. Such -rocks were in all succeeding formations produced under water and by -accumulations of the remains of plants and the hard parts of animals, -in strictly sedimentary beds, usually formed slowly and without -mechanical disturbance. Hence we may infer that aquatic life at least -existed in this early period, and as there must have been land and -water, shallows and deep seas, there may have been scope for various -kinds of living beings. The Grenville period is, however, separated -from the succeeding Huronian by a great interval, occupied mainly by -volcanic ejections and earth-movements; so that our Grenville series, -if it contains organic remains, may be supposed to afford species -differing from those of the Huronian, and to form a sort of oasis in -the desert of the early pre-Cambrian world. We find that the limestones -of this age actually contain remains supposed to be of animal origin. -They were first found in Canada, which contains the largest and best -exposed area of these rocks in the world, and were brought under the -notice of geologists by the late Sir William E. Logan, the first -director of the Geological Survey of that country. - -In anticipation of details to be given later, the story of this -discovery and its announcement may here be given in brief - -As early as 1858, Sir William Logan had begun to suspect that certain -laminated bodies found in the Laurentian limestones of the Grenville -series might be of organic origin. The points which struck him were -these: They differed from any known laminated concretions; they -resembled the "Stromatoporæ" or layer-corals of the lower Palæozoic -rocks next in succession to the Laurentian and Huronian; the forms were -similar in all the specimens, while the mineralizing substances were -different; they were found only in the limestone, and specially in one -of the three great beds known in the formation, the upper limestone -of the Grenville system. He exhibited specimens, and mentioned these -probabilities at the meeting of the American Association in 1859. In -1862 it was suggested to Logan that the microscopic structure of some -of the best preserved examples should be studied, and slices were -accordingly prepared and submitted to the writer for examination. -They revealed in the calcareous laminæ of the specimens complicated -systems of canals or tubes filled with mineral matter, which appeared -to be similar to those that Carpenter had recognised in the thickened -parts of the shells of modern Foraminifera. This clew being followed, -large numbers of slices of the supposed fossils and of the containing -limestone and of similar limestones from other parts of the world were -examined. - -The writer also visited the localities of "Eozoon," and studied its -mode of occurrence _in situ_. The facts ascertained were communicated -to the Geological Society of London, the name "Eozoon Canadense" -being proposed for the species. Its description was accompanied by a -paper on the geological conditions by Logan, and one on the chemical -conditions by Sterry Hunt, while supplementary notes were added by -the late Dr. Carpenter and Professor T. Rupert Jones. Thus launched -on the scientific world, "Eozoon" at once became a fertile subject -of discussion, and volumes of more or less controversial literature -have appeared respecting it. It still has its friends and opponents, -and this may long continue, as so few scientific men are sufficiently -acquainted on the one hand with the possibilities and conditions of the -preservation of fossils in crystalline rocks, and on the other hand -with the structures of modern "Protozoa." Thus, few are in a position -to form an independent judgment, and "Eozoon" has met with some -scepticism on the part both of biological and mineralogical specialists. - -To aid us in forming an opinion, it will be necessary to consider the -oldest known strata of the earth's crust, and the evidence which they -afford of the condition of the world when they were deposited. As -preliminary to this, we may look at the following table of pre-Cambrian -formations in Canada. - - -SUCCESSION OF PRE-CAMBRIAN ROCKS IN CANADA, AS UNDERSTOOD UP TO 1896. - -(_In descending order._) - - ---------------------------------------------------- - PALÆOZOIC. - { Etcheminian in New Brunswick, _Kewenian_ or _Upper - { Copper-bearing Series_ of Lake Superior, _Signal Hill - { Series_ of Newfoundland. _Chuar_, and _Grand Cañon_ - { rocks of Colorado, etc. - { - { Red and greenish Sandstones and Shales, Conglomerates, - { Igneous Outflows and Ash-rocks. Bivalve - { Crustacea, Mollusks, Worms, Sponges, Cystideans, - { Zoophytes, Protozoa, Cryptozoon. - { ---------------------------------------------------- - (_Unconformity._) - ---------------------------------------------------- - EOZOIC. - { Huronian, including _Hastings_ of Ontario, _Coldbrook_ - { and _Coastal_ of New Brunswick, _Algonkian_ (in part). - { Conglomerates, Hard Sandstones, Shales and Schists, - { Iron Ores, Coarse Limestones, Igneous Outflows, and - { Ash-rocks. Worms, Sponges, Zoophytes, and Protozoa - { (Cryptozoon or Eozoon). - ---------------------------------------------------- - (_Unconformity [?]_) - ---------------------------------------------------- - EOZOIC. - { Grenvillian or Upper Laurentian. - { Gneiss, Hornblendic and Micaceous Schists, Limestones, - { Quartzite, Iron Ores, Graphite. Eozoon, Archæozoon, - { Archæospherinæ, Archæophyton. - ---------------------------------------------------- - _Unconformity._ - ---------------------------------------------------- - AZOIC - { Archæan or Lower Laurentian. - { Gneiss, Hornblende Schists, with many igneous or - { igneo-aqueous intrusions. - - - - - _THE FOUNDATIONS OF THE CONTINENTS, AND - THEIR GENERAL TESTIMONY AS TO LIFE_ - - - - - IV - - _THE FOUNDATIONS OF THE CONTINENTS, AND - THEIR GENERAL TESTIMONY AS TO LIFE_ - - -That the reader may be enabled better to understand the relation of -the old foundations or pillars of the earth to the beginning of life, -and the preservation of the remains of the earliest animals, it may be -well to reverse the method we have hitherto followed, and to present -a theoretical or ideal historical sketch of the early history of the -earth, beginning with that stage in which it may be supposed to have -been a liquid mass, considerably larger than it is at present, and -intensely heated, and surrounded by a vast vaporous envelope composed -of all the substances capable of being resolved by its heat into a -gaseous condition--a smooth and shining spheroid, invested with an -enormous atmosphere. - -In such a condition its denser materials, such as the heavier metals, -would settle toward the centre, and the surface would consist of -lighter material composed of the less dense and more oxidizable -substances combined with oxygen, and similar in character and -appearance to the slag which forms on the surface of some ores in the -process of smelting. Of this slaggy material there might, however, be -different layers more or less dense in proceeding from the interior to -the surface. This molten surface would, of course, radiate heat into -space; and as it would naturally consist of the least fusible matters, -these would begin to form a solid crust. We may imagine this crust at -first to be smooth and unbroken, though such a condition could scarcely -exist for any length of time, as the hardened crust would certainly be -disturbed by ascending currents from within, and by tidal movements -without. Still, it might remain for ages as a spheroidal crust, -presenting little difference of elevation or depression in comparison -with its extent. When it became sufficiently thick and cool to allow -water to lie on its surface, new changes would begin. The water so -condensed would be charged with acid substances which would begin to -corrode the rocky surface. Penetrating into crevices and flashing into -steam as it reached the heated interior, it would blow up masses and -fragments of stone, and would perhaps force out and cause to flow over -the surface beds of molten material from below the crust, and differing -somewhat from it in their composition. All this aqueous work would -accelerate the cooling and thickening of the crust, and at length a -universal or almost universal heated ocean would envelope the globe, -and so far as its surface was concerned, the reign of water would -replace that of fire. We may pause here to consider the probable nature -of the earth's crust in this condition. - -The substance most likely to predominate would be silica or quartz, -one of the lighter and most infusible materials of the crust; but -which, heated in contact with alumina, lime, potash, and other earths -and alkalis, forms fusible slags, enamels and glasses. One of these, -composed of silica, alumina, and potash, or soda, was long ago named -by the German miners felspar, a name which it still retains, though -now several distinct kinds of it are distinguished by different names. -Another is a compound of silica with magnesia and lime, forming the -mineral known as Amphibole or Hornblende, and by several other names, -according to its colour and crystalline form. In many deep-seated -rocks these minerals are formed together, and having crystallized -out separately give a spotted and granular character to the mass. -Naturally colourless, all these minerals, and especially the felspar -and hornblende, are liable to be coloured with different oxides of -iron, the felspar usually taking a reddish, and the hornblende a -greenish or blackish hue. Now, if we examine a fragment of the oldest -or fundamental gneiss or granite, we shall see glassy grains of quartz, -reddish or white flat-surfaced crystals of felspar, and dark-coloured -prisms of hornblende. When destitute of any arrangement in layers, the -rock is granite; when arranged more or less in flakes or laminæ, it is -gneiss, the structure of which may arise either from its having been -formed in successive beds, or from its having been flattened or drawn -out by pressure. These structures can be seen more or less distinctly -in any ordinary coarse-grained granite, or with the lens or microscope -in finer varieties. - -The Lower Laurentian rocks of our section consist essentially of the -materials above described, with a vast variety in the proportions -and arrangements of the constituent minerals. There is, there-fore, -nothing to prevent us from supposing that these rocks are really -remains of the lower portions of the original crust which first formed -on the surface of our cooling planet, though the details of their -consolidation and the possible interactions of heat and heated water -may admit of much discussion and difference of opinion. - -But after the formation of a crust and its covering in whole or in -part with heated water, other changes must occur, in order to fit the -earth for the abode of life. These proceeded from the tensions set -up by the contraction and expansion of the interior heated nucleus -and the solid crust--a complicated and difficult question, when we -consider its laws and their mode of operation, but which resulted in -the folding and fracturing of the crust along long lines which are -parts of great circles of the earth, running in N.E. and S.W. and N.W. -and S.E. directions; and these ridges, which in the earliest Archæan -period must have attained to great height and very rugged outlines, -formed the first rudiments of our mountain chains and continents. Those -constituting the Laurentian nucleus of North America--a very simply -outlined continent--form a case in point (Fig. 18). - -The elevation of these mountain ridges forced the waters to recede into -the lower levels. As the old psalm of creation has it,-- - - "The mountains ascend, - the valleys descend into - the place Thou hast founded - for them," - -and so sea-basins and land were produced. - -Milton merely paraphrases this when he says,-- - - "The mountains huge appear - Emergent, and their broad, bare backs upheave - Into the clouds; their tops ascend the sky. - So high as heaved the tumid hills, so low - Down sunk a hollow bottom wide and deep. - Capacious bed of waters." - -Englishmen have been accused of taking their ideas of creation from -Milton rather than from nature or the Bible. Milton had not the -guidance of modern geology. His cosmology is entirely that of a close -student of the Biblical narrative of creation. He is in many respects -the best commentator on the early chapters of Genesis, because he -had a very clear conception of the mind of the writer, and the power -of expressing the ideas he derived from the old record. For the same -reason he is the greatest bard of creation and primitive man, and -surprisingly accurate and true to nature. - -[Illustration: Fig. 18.--_Map of Laurentian, North America._ - -Showing the protaxis or nucleus of the continent.] - -Then began the great processes of denudation and sedimentation to which -we owe the succeeding rock formations. The rains descended on the -mountain steeps, and washed the decaying rocks as sand, gravel and mud -into the rivers and the sea. The sea itself raged against the coasts, -and cut deeply into their softer parts; and all the detritus thus -produced by atmospheric and marine denudation was spread out by the -tides and currents in the bed of the ocean, and its gulfs and seas, -forming the first aqueous deposits, while the original land must have -been correspondingly reduced. - -The sea might still be warm, and it held in solution or suspension -somewhat different substances from those now present in it, and the -land was at first a mere chaos of rocky crags and pinnacles. But so -soon as the temperature of the waters fell somewhat below the boiling -point, and as even a little soil formed in the valleys and hollows of -the land, there was scope for life, provided that its germs could be -introduced. - -On a small scale there was something of this same kind in the sea -and land of Java, after the great eruption of Krakatoa, in 1883. The -bare and arid mountain left after the eruption, began, in the course -of a year, to be occupied by low forms of vegetable life, gradually -followed by others, and verdure was soon restored. The once thickly -peopled sea-bottom, so prolific of life in these warm seas, but -buried under many feet of volcanic ashes and stones, soon began to be -re-peopled, and is now probably as populous as before. But in this -case there were plenty of spores of lichens, mosses, and other humble -plants to be wafted to the desolate cone, and multitudes of eggs and -free-swimming germs of hundreds of kinds of marine animals to re-people -the sea-bottom. Whence were such things to come from to occupy the -old Archæan hills and sea-basins? and all our knowledge of nature -gives us no answer to the question, except that a creative power must -have intervened; but in what manner we know not. That this actually -occurred, we can, however, be assured by the next succeeding geological -formation. We have seen that the granitic and gneissic ridges could -furnish pebbles, sand, and clay, and these once deposited in the -sea-bottom could be hardened into conglomerate, sandstone and slate. -But beside these we have in the next succeeding or Upper Laurentian -formation rocks of a very different character. We have great beds of -limestone and iron ore, and deposits, of carbon or coaly matter, now -in the peculiar state of graphite or plumbago, and it is necessary -for us to inquire how these could originate independently of life. In -modern seas limestone is forming in coral reefs, in shell beds, and in -oceanic chalky ooze composed of minute microscopic shells; but only in -rare and exceptional instances is it formed in any other way; and when -we interrogate the old limestones and marbles which form parts of the -land, they give us evidence that they also are made up of calcareous -skeletons of marine animals or fragments of these. - -[Illustration: Fig. 19.--_Distribution of Grenville Limestone in -the district north of Papineauville, with section showing supposed -arrangement of the beds._] - -Scale of Map 7 miles to one inch. See also Dr. Bonney's paper, _Geol. -Mag._, July, 1895. - -_Dotted area:_ Limestone. _Horizontal lines:_ Upper gneiss (fourth -gneiss of Logan). _Vertical lines:_ Lower gneiss (third gneiss of -Logan). _Diagonal lines:_ Overlying Cambrian and Cambro-Silurian -(Ordovician). (See also Fig. 19A.) - -Now when we find in the Grenvillian series, the first oceanic group of -beds known to us, great and widely extended limestones, thousands of -feet in thickness, and rivalling in magnitude those of any succeeding -period, we naturally infer that marine life was at work. No doubt -the primitive sea contained more lime and magnesia than the present -ocean holds in solution; but while this might locally favour the -accumulation of inorganic limestones, it cannot account for so great -and extensive deposits. On the other hand, a sea rich in lime would -have afforded the greatest facilities for the growth of those marine -plants which accumulate lime, and through these for the nutrition of -animals forming calcareous shells or corals. Thus we have presumptive -evidence that there must have been in the Upper Laurentian sea -something corresponding to our coral reefs and shell-beds, whatever -this something may have been. - -These limestones, however, demand more particular notice (Fig. 19). - -One of the beds measured by the officers of the Geological Survey is -stated to be 1,500 feet in thickness, another is 1,250 feet thick, -and a third 750 feet; making an aggregate of 3,500 feet.[14] These -beds may be traced, with more or less interruption, for hundreds of -miles. Whatever the origin of such limestones, it is plain that they -indicate causes equal in extent, and comparable in power and duration, -with those which have produced the greatest limestones of the later -geological periods. Now, in later formations, limestone is usually an -organic rock, accumulated by the slow gathering from the sea-water, -or its plants, of calcareous matter, by corals, foraminifera, or -shell-fish, and the deposition of their skeletons, either entire or -in fragments on the sea-bottom. The most friable chalk and the most -crystalline limestones have alike been formed in this way. We know of -no reason why it should be different in the Laurentian period. When, -therefore, we find great and conformable beds of limestone, such as -those described by Sir William Logan in the Laurentian of Canada, we -naturally imagine a quiet sea-bottom, in which multitudes of animals of -humble organization were accumulating limestone in their hard parts, -and depositing this in gradually increasing thickness from age to age. -Any attempts to account otherwise for these thick and greatly extended -beds, regularly interstratified with other deposits, have so far been -failures, and have arisen either from a want of comprehension of the -nature and magnitude of the appearances to be explained, or from the -error of mistaking the true bedded limestones for veins of calcareous -spar. - -[Footnote 14: Logan: "Geology of Canada," p. 45.] - -[Illustration: Fig. 19A.--_Attitude of Limestone at Côte St. Pierre_ -(see Map, p. 88). - -(_a_) Gneiss band in the Limestone, (_b_) Limestone with Eozoon. (_c_) -Diorite and Gneiss.] - -Again, in the original molten world, it seems likely that most of -the carbon present--at least, at the surface--was in the atmosphere -in the gaseous form of carbon dioxide. This might be dissolved by -the rain and other waters; but we know in the modern world no agency -which can decompose this compound and reduce it to ordinary carbon -or coal, except that of living plants, which are always carrying on -this function to an enormous extent. We know that all our great beds -of coal and peaty matter are composed of the remains of plants which -took their carbon from the air and the waters in past times. We also -know that this coaly vegetable matter may, under the influence of heat -and pressure, when buried in the earth, be converted into anthracite -and into graphite, and even into diamond. It is true that an eminent -French chemist[15] has shown that graphite and hydrocarbons may be -produced from some of the metallic compounds of carbon which may have -been formed under intense heat in the interior of the earth, by the -subsequent action of water on such compounds; but there is nothing to -show that this can have occurred naturally, unless in very exceptional -cases. Now in the Grenvillian system in Canada there is not only a -vast quantity of carbon diffused through the limestones, and filling -fissures in other rocks, into which it seems to have been originally -introduced as liquid bitumen, but also in definite beds associated with -earthy matter, and sometimes ten to twelve feet thick. The occurrence -of this large amount of carbon warrants us in supposing that it -represents a vast vegetable growth, either on the land or in the sea, -or both. - -[Footnote 15: Henri Moissan, "Proceedings Royal Society," June, 1896,] - -In like manner, in later geological periods, beds of iron ore are -generally accumulated as a consequence of the solvent action of -acids produced by vegetable decay, as in the clay ironstones of the -coal formation and the bog iron ores of later times. Thus the beds -of magnetic iron occurring in the Upper Laurentian may be taken as -evidences, not of vegetable accumulation, but of vegetable decay. - -May not also the great quantity of calcium phosphate mined in the -Grenville series in Canada, indicate, as similar accumulations do in -later formations, the presence of organisms having skeletons of bone -earth? - -With reference to the carbon and iron ore of the Grenville series, I -may quote the following from a paper published in the _Journal of the -Geological Society of London_ in 1870:-- - -"The quantity of graphite in the Upper Laurentian series is enormous. -In a recent visit to the township of Buckingham, on the Ottawa River, -I examined a band of limestone believed to be a continuation of that -described by Sir W. E. Logan as the Green Lake Limestone. It was -estimated to amount, with some thin interstratified bands of gneiss, -to a thickness of 600 feet or more, and was found to be filled with -disseminated crystals of graphite and veins of the mineral to such -an extent as to constitute in some places one-fourth of the whole; -and making every allowance for the poorer portions, this band cannot -contain in all a less vertical thickness of pure graphite than from -twenty to thirty feet. In the adjoining township of Lochaber Sir W. E. -Logan notices a band from twenty-five to thirty feet thick, reticulated -with graphite veins to such an extent as to be mined with profit for -the mineral. At another place in the same district a bed of graphite -from ten to twelve feet thick, and yielding twenty per cent, of the -pure material, is worked. When it is considered that graphite occurs in -similar abundance at several other horizons, in beds of limestone which -have been ascertained by Sir W. E. Logan to have an aggregate thickness -of 3,500 feet, it is scarcely an exaggeration to maintain that the -quantity of carbon in the Laurentian is equal to that in similar areas -of the Carboniferous system. It is also to be observed that an immense -area in Canada appears to be occupied by these graphitic and Eozoon -limestones, and that rich graphitic deposits exist in the continuation -of this system in the State of New York; while in rocks believed to be -of this age near St. John, New Brunswick, there is a very thick bed -of graphitic limestone, and associated with it three regular beds of -graphite, having an aggregate thickness of about five feet.[16] - -[Footnote 16: Matthew, in _Quart. Journ. Geol. Soc._, vol. xxi. p. 423. -"Acadian Geology," p. 662.] - -"It may fairly be assumed that in the present world, and in those -geological periods with whose organic remains we are more familiar than -with those of the Laurentian, there is no other source of unoxidized -carbon in rocks than that furnished by organic matter, and that this -has obtained its carbon in all cases, in the first instance, from the -deoxidation of carbonic acid by living plants. No other source of -carbon can, I believe, be imagined in the Laurentian period. We may, -however, suppose either that the graphitic matter of the Laurentian -has been accumulated in beds like those of coal, or that it has -consisted of diffused bituminous matter similar to that in more -modern bituminous shales and bituminous and oil-bearing limestones. -The beds of graphite near St. John, some of those in the gneiss at -Ticonderoga in New York, and at Lochaber and Buckingham and elsewhere -in Canada, are so pure and regular that one might fairly compare them -with the graphitic coal of Rhode Island. These instances, however, are -exceptional, and the greater part of the disseminated and vein graphite -might rather be compared in its mode of occurrence to the bituminous -matter in bituminous shales and limestones. - -"We may compare the disseminated graphite to that which we find in -those districts of Canada in which Silurian and Devonian bituminous -shales and limestones have been metamorphosed and converted into -graphitic rocks not dissimilar to those in the less altered portions of -the Laurentian.[17] In like manner it seems probable that the numerous -reticulating veins of graphite may have been formed by the segregation -of bituminous matter into fissures and planes of least resistance, in -the manner in which such veins occur in modern bituminous limestones -and shales. Such bituminous veins occur in the Lower Carboniferous -limestone and shale of Dorchester and Hillsborough, New Brunswick, with -an arrangement very similar to that of the veins of graphite; and in -the Quebec rocks of Point Levi, veins attaining to a thickness of more -than a foot are filled with a coaly matter having a transverse columnar -structure, and regarded by Logan and Hunt as an altered bitumen. -These Palæozoic analogies would lead us to infer that the larger part -of the Laurentian graphite falls under the second class of deposits -above mentioned, and that, if of vegetable origin, the organic matter -must have been thoroughly disintegrated and bituminized before it was -changed into graphite. This would also give a probability that the -vegetation implied was aquatic, or at least that it was accumulated -under water. - -[Footnote 17: Granby, Melbourne, Owl's Head, etc., "Geology of Canada," -1863, p. 599.] - -"Dr. Hunt has, however, observed an indication of terrestrial -vegetation, or at least of subaërial decay, in the great beds of -Laurentian iron ore. These, if formed in the same manner as more modern -deposits of this kind, would imply the reducing and solvent action of -substances produced in the decay of plants. In this case such great -ore beds as that of Hull, on the Ottawa, 70 feet thick, or that near -Newborough, 200 feet thick,[18] must represent a corresponding quantity -of vegetable matter which has totally disappeared. It may be added that -similar demands on vegetable matter as a deoxidizing agent are made -by the beds and veins of metallic sulphides of the Laurentian, though -some of the latter are no doubt of later date than the Laurentian rocks -themselves. - -[Footnote 18: "Geology of Canada," 1863.] - -"It would be very desirable to confirm such conclusions as those above -deduced by the evidence of actual microscopic structure. It is to be -observed, however, that when, in more modern sediments, algæ have -been converted into bituminous matter, we cannot ordinarily obtain -any structural evidence of the origin of such bitumen, and in the -graphitic slates and limestones derived from the metamorphosis of -such rocks no organic structure remains. It is true that, in certain -bituminous shales and limestones of the Silurian system, shreds of -organic tissue can sometimes be detected, and in some cases, as in -the Lower Silurian limestone of the La Cloche mountains in Canada, -the pores of brachiopodous shells and the cells of corals have been -penetrated by black bituminous matter, forming what may be regarded as -natural injections, sometimes of much beauty. In correspondence with -this, while in some Laurentian graphitic rocks,--as, for instance, -in the compact graphite of Clarendon,--the carbon presents a curdled -appearance due to segregation, and precisely similar to that of the -bitumen in more modern bituminous rocks, I can detect in the graphitic -limestones occasional fibrous structures which may be remains of -plants, and in some specimens vermicular lines, which I believe to be -tubes of Eozoon penetrated by matter once bituminous, but now in the -state of graphite. - -"When Palæozoic land-plants have been converted into graphite, they -sometimes perfectly retain their structure. Mineral charcoal, with -structure, exists in the graphitic coal of Rhode Island. The fronds of -ferns, with their minutest veins perfect, are preserved in the Devonian -shales of St. John, in the state of graphite; and in the same formation -there are trunks of Conifers (_Dadoxylon ouangondianum_) in which the -material of the cell-walls has been converted into graphite, while -their cavities have been filled with calcareous spar and quartz, the -finest structures being preserved quite as well as in comparatively -unaltered specimens from the coal-formation.[19] No structures so -perfect have as yet been detected in the Laurentian, though in the -largest of the three graphitic beds at St. John there appear to be -fibrous structures which I believe may indicate the existence of -land-plants. This graphite is composed of contorted and slicken-sided -laminæ, much like those of some bituminous shales and coarse coals; and -in these there are occasional small pyritous masses which show hollow -carbonaceous fibres, in some cases presenting obscure indications of -lateral pores. I regard these indications, however, as uncertain; and -it is not as yet fully ascertained that these beds at St. John are -on the same geological horizon with the Grenville series of Canada, -though they certainly underlie the Cambrian series of the St. John or -Acadian group, and are separated from it by beds having the character -of the Huronian, and thus come, approximately at least, into the same -geological position. - -[Footnote 19: "Acadian Geology," p. 535. In calcified specimens the -structures remain in the graphite after decalcification by an acid.] - -"There is thus no absolute impossibility that distinct organic tissues -may be found in the Laurentian graphite, if formed from land-plants, -more especially if any plants existed at that time having true woody -or vascular tissues; but it cannot with certainty be affirmed that -such tissues have been found. It is possible, however, that in the -Laurentian period the vegetation of the land may have consisted wholly -of cellular plants, as, for example, mosses and lichens; and if so, -there would be comparatively little hope of the distinct preservation -of their forms or tissues, or of our being able to distinguish the -remains of land-plants from those of Algæ. The only apparent plant -of the Laurentian to which a name has been given, _Archæophyton_ of -Britton, from New Jersey, consists of ribbon-like strips, destitute -of apparent structure, and which, if they are of vegetable origin, -may have belonged to either of the leading divisions of the vegetable -kingdom. I have found similar flat frond-like objects in the limestone -of the Grenville series, at Lachute, in Canada. - -"We may sum up these facts and considerations in the following -statements:--First, that somewhat obscure traces of organic structure -can be detected in the Laurentian graphite; secondly, that the general -arrangement and microscopic structure of the substance corresponds with -that of the carbonaceous and bituminous matters in marine formations -of more modern date; thirdly, that if the Laurentian graphite has been -derived from vegetable matter, it has only undergone a metamorphosis -similar in kind to that which organic matter in metamorphosed sediment -of later age has experienced; fourthly, that the association of the -graphitic matter with organic limestone, beds of iron ore, and metallic -sulphides, greatly strengthens the probability of its vegetable origin; -fifthly, that when we consider the immense thickness and extent of -the Eozoonal and graphitic limestones and iron ore deposits of the -Laurentian, if we admit the organic origin of the limestone and -graphite, we must be prepared to believe that the life of that early -period, though it may have existed under low forms, was most copiously -developed, and that it equalled, perhaps surpassed, in its results, in -the way of geological accumulation, that of any subsequent period." - -[Illustration: Figs. 20 _and_ 21.--_Bent and dislocated Quartzite, -in contorted schists interstratified with Grenville Limestone, near -Montebello._ - -The Quartzites have been broken and displaced, while the schists have -been bent and twisted. In the immediate vicinity the same beds may be -seen slightly inclined and undisturbed.] - -Let us take, in connection with all this, the fact that we are dealing -with the deposits of the earliest ocean known to us--an ocean warm and -abounding in the mineral matters suitable for the skeletons of humble -animals, and fitted to nourish aquatic plants. The conditions were -certainly favourable to an exuberant development of the lower forms -of marine life; and in later times, when such conditions prevail, we -generally find that life has been introduced to take advantage of them. -The prudent farmer does not usually allow his best pasture to remain -untenanted with flocks and herds, and the Great Husbandman of nature -has, so far as we know, been similarly careful. - -I add two sections showing the local disturbances of beds of quartzite -and schist associated with the Grenville limestones (Figs. 20 and 21, -page 103). - - - - - _PROBABILITIES AS TO LAURENTIAN LIFE, AND - CONDITIONS OF ITS PRESERVATION_ - - - - - V - - _PROBABILITIES AS TO LAURENTIAN LIFE, AND - CONDITIONS OF ITS PRESERVATION_ - - -We have seen that the mineral constitution of the Upper Laurentian -affords evidence that in this age there were already land and water, -and that the processes by which the land is being worn down, and its -materials deposited on the sea-bottom, were in full operation; while -the absence of any evidence of violent wave-action, and the presence of -thick deposits of limestone, coaly matter, iron ore, and fine-grained -beds of sediment, indicates a time of rest and quiescence. All these -conditions were favourable to the presence of life, and we should -expect to find in such a period some sign of its commencement. - -But here we are met by a formidable difficulty. If the beds of the -Grenville series were originally deposits in a quiet sea, they are, as -now existing in the old Laurentian hills and valleys, very much changed -from their original condition. They have, in short, experienced the -changes known to geologists by the formidable word metamorphism, -whereby they have lost the more obvious characters of ordinary aqueous -deposits, and have assumed new and strange forms. Dr. Adams, of -Montreal, has taken the pains to collect a number of chemical analyses -of the gneisses and schists or crystalline slates of the Grenville -series, and finds that, however unlike to more modern shales and clays, -they have substantially the same chemical composition. Now if they were -originally such shales and clays, it has happened to them that the -ingredients of the clays have rearranged themselves in new forms and -become crystalline. We are familiar in a small way with such changes -when brick clay, over-heated in the kiln, becomes fused into slag -or vitrified; and if such slag were allowed to cool very slowly, it -would present different kinds of crystalline minerals. We actually see -changes of this kind in the substance of bricks which have been long -exposed to intense heat in the walls of furnaces. Now in the crust of -the earth, very old rocks, buried under newer deposits, and exposed -to the heat of the interior molten rocks, experience such changes on -a great scale; and there is one kind of influence present in the -bowels of the earth which we in our experiments cannot easily imitate -or understand, namely, the action of superheated water prevented by -pressure from escaping as steam, and permeating the whole substance of -deposits, which are thus baked at a high temperature in presence of -water, instead of being exposed to mere dry heat, as in our kilns and -furnaces. The study of the partial changes which have passed on later -sediments where in contact with volcanic masses once intensely heated, -enables us to understand the greater and more extensive metamorphism -of the oldest rocks. Thus a mere mud becomes glorified by metamorphic -crystallization into a micaceous schist. We have taken ordinary clay -as an example; but under the same processes sand has been converted -into a compact quartzite, ordinary limestone into crystalline marble, -clay-ironstone into magnetic iron ore, coal into graphite, and lavas or -volcanic ashes into hard crystalline granites, gneisses, or pyroxene -rocks or hornblendic schists, according to their original composition. -There may exist portions of these old rocks which have been exempt -from such alteration, but hitherto we have not been able to find them, -and they are probably under the ocean bed, or deeply burled beneath -later rocks, while the parts exposed are precisely those which have -by their crumpling and pressure, and the influence of internal heat, -become most hardened and altered, and have therefore best resisted -denudation. We need not therefore be astonished if any organic remains -originally present in such rocks should have perished, or should have -been subjected to such changes of composition and form as to have -altogether lost their original characters. The searcher for fossils -in such rocks has to expect that these can have been preserved only -under very rare and exceptional circumstances. We have now to consider -what these circumstances are, and for simplicity may suppose that we -are endeavouring to discover in a crystalline limestone the remains -of animals having a skeleton of limestone, as is the case with most -shell-fishes and corals, and with many Protozoa and marine worms. In -regard to these, we have to consider what may happen to them when they -are imbedded in calcareous marl or ooze, or the limestone which results -from the hardening of such materials; and we have to bear in mind that -such organisms usually consist of hard, stony walls or partitions, -enclosing cavities originally filled with the soft parts of the animal -which may be supposed to have disappeared by decay before or during the -mineralization of its skeleton. - -So long as the imbedding mass continues soft and incoherent, shells, -corals, etc., can be recovered in a condition similar to that of recent -specimens, except that they may have become bleached in colour and -brittle in texture, owing to the removal of organic matter intimately -associated with the lime, and that their cavities may have been filled -with sand or silt washed into them, or with calcite or calcareous spar -introduced in solution in water. But if the containing mass has become -a hard stone, the material filling the interior of our shell or coral -has experienced a similar change; and when we break open the stone, -we may obtain the specimen, now hard, solid, and heavy, but still -showing more or less of its outer surface and markings, and possibly to -some extent also its internal structure when it is sliced and studied -under the microscope. But if the whole mass has been metamorphosed, -and has become crystalline, the contained fossil and its contents may -have experienced a similar change, and may have so coalesced with the -containing matrix that it is no longer separable from it. Even in this -case, however, if the whole is reduced to a thin transparent slice -and examined microscopically, some traces may be found of the external -and internal limiting lines of the fossil, and even of its minute -structures, which often cause it to present an appearance granular, -cellular, or otherwise different from that of the enclosing matrix. It -requires, however, both skill and care to detect organic remains in -such circumstances, and they may often escape observation, except when, -as in many old crystalline limestones, the fossils are darkened in -whole or in part with coaly matter derived from the decay of their own -organic substance. The crystalline Trenton limestone of Montreal, used -there as a building stone, is an excellent example (Fig. 22). - -[Illustration: Fig. 22.--_Section of "Trenton Limestone" (magnified)._ - -Showing its composition of fragments of calcareous fossils.] - -[Illustration: Fig. 23.--_Diagram of different States of Fossilization -of the Cell of a Tubulate Coral._ - -(_a_) Natural condition, (_b_) Cell filled with calcite. (_c_) Walls -calcite, filling silica. (_d_) Walls silica, filling calcite. (_e_) -Both walls and calcite silica. All these conditions are found in the -fossil corals of the corniferous Limestone of Canada--Middle Permian.] - -It is otherwise, however, when the calcareous fossils have been filled -or injected with some mineral matter different from the matrix, as, for -example, silica or some silicate, oxide or sulphide of iron. In this -case the texture, colour, or hardness of the filling appear different -from those of the limestone, and may be seen in a fresh fracture or -polished slice; or when the rock is weathered, the hard mineralizing -substance may project from the surface of the specimens, or may be -disclosed by treating the surface with a weak acid. The figures here -given may suffice to show some of these conditions of mineralization -in ordinary limestones, and the effects which they produce (Fig. 23). - -The mineral matters which thus aid in preserving fossils are of various -kinds, and the whole subject is a very curious one; but for the present -we may content ourselves with two kinds of mineralization--that by -silicates and that by magnesian limestone or dolomite. - -From the bottom of modern seas the dredge often brings up multitudes -of minute shells, especially those of the simple gelatinous Protozoa, -known as Foraminifera, whose internal cavities and pores have been -filled with a greenish mineral composed of silica, iron and potash, -combined with water (or, chemically speaking, a hydrous silicate of -iron and potassium), which is named _glauconite_ from its bluish-green -colour--a name which we shall do well to remember. In such compounds, -bases of similar chemical properties often replace one another, so -that various glauconites differ somewhat in composition, the iron -being in part often replaced by alumina or magnesia, and the potash by -soda. The combined water also differs somewhat in its percentage. When -minute shells fossilized in this way are treated with an acid so as to -remove the calcareous shell itself, the enclosed silicate remains as a -beautiful cast or core, representing all the forms of the interior, -and any pores that may have penetrated the walls, and also perfectly -representing the soft gelatinous body of the animal which once tenanted -the shells (Fig. 24). (See also Fig. 25 at end of chapter.) - -[Illustration: Fig. 24.--_Cast of Cavities of Polystomella in -Glauconite (magnified)._ - -After a photograph from Dr. Carpenter, and mounted specimens from his -collection.] - -When we examine oceanic sediments of older date, we find similar -fillings in limestones, chalks, and sandstones of various ages, some -of the latter containing glauconite so abundantly as to bear the name -of green-sands, from their colour; and in these older examples we more -frequently find alumina and magnesia occupying a large place in the -mineralizing silicate. Fig. 24A gives two illustrations of this--one -a crinoidal stem from the Silurian of New Brunswick, injected with a -silicate of alumina, iron, magnesia and potash; the other a spiral -shell from more ancient perhaps Cambrian rocks in Wales, filled with a -silicate apparently more nearly related to serpentine. Further examples -will be referred to in an appended note. - -[Illustration: Fig. 24A.--(_a_) _Joint of Crinoid injected with a -Hydrous Silicate, Silurian, Pole Hill, New Brunswick._ (× 25.) - -(_b_) _Spiral Shell injected with a Hydrous Silicate allied to -Serpentine, near Llangwyllog, North Wales,_ (× 25.)] - -We may now consider shortly the relation of dolomite, or the mixed -carbonates of lime and magnesia, to the preservation of fossils. The -presence of dolomite or magnesian limestone in these beds does not -affect the conclusion as to their probable organic origin. This form of -limestone occurs abundantly in later formations, and is even forming in -connection with coral deposits in the modern ocean. - -Dana has shown this by his observations on the occurrence of dolomite -in the elevated coral island of Matea in Polynesia,[20] under -circumstances which show that it was formed in the lagoon of an ancient -coral atoll, or ring-shaped island, while he finds that coral and -coral sands of the same elevated reef contain very little magnesia. -He concludes that the introduction of magnesia into the consolidating -under-water coral sand or mud has apparently taken place--"(1) In -sea-water at the ordinary temperature; and (2) without the agency of -any other mineral water except that of the ocean"; but the sand and -mud were those of a lagoon in which the saline matter was in process -of concentration by evaporation under the solar heat. Klement has -more recently taken up this fact in the way of experiment, and finds -that, while in the case of ordinary calcite this action is slow -and imperfect, with the aragonite which constitutes the calcareous -framework of certain corals,[21] and at temperatures of 60° or over, -it is very rapid and complete, producing a mixture of calcium and -magnesium carbonates, from which a pure dolomite more or less mixed -with calcite may subsequently result.[22] - -[Footnote 20: "Corals and Coral Islands," p. 356, etc.] - -[Footnote 21: Aragonite, like ordinary limestone, is calcium carbonate, -but its atoms seem to be differently arranged, so as to make it a -less stable compound, and it has a different crystalline form. Some -calcareous organisms are composed of aragonite, others of ordinary -calcite.] - -[Footnote 22:"Bulletin Geol. Soc. Belgium," vol. ix. (1895, p. 3). Also -notice in _Geol. Mag._, July, 1895, p. 329.] - -I regard these observations as of the utmost importance in reference to -the relations of dolomite with fossiliferous limestones, and especially -with those of the Grenville series. The waters of the Laurentian ocean -must have been much richer in salts of magnesium than those of the -present seas, and the temperature was probably higher, so that chemical -changes now proceeding in limited lagoons might have occurred over -much larger areas. If at that time there were, as in later periods, -calcareous organisms composed of aragonite, these may have been -destroyed by conversion into dolomite, while others more resisting were -preserved, just as a modern _Polytrema_ or _Balanus_ might remain, when -a coral to which it might be attached would be dolomitized, or might -even be removed altogether by sea-water containing carbonic acid. There -is reason to believe that this last change sometimes takes place in -the deeper parts of the ocean at present. This would account for the -persistence of Eozoon and its fragments, when other organisms may have -perished, and also for the frequent filling of the canals and tubuli -with the magnesian carbonate. - -The main point here, however, for our present purpose is that, when a -calcareous shell or skeleton has been thus infiltrated with a silicate, -it becomes imperishable, so that any amount of alteration of the -containing limestone short of its absolute fusion would not suffice -to destroy an organism once injected with silicious matter. Thus the -occasional persistence of silicified fossils in highly metamorphosed -limestones is in no respect contradictory to the general fact, that -when not preserved by silicious infiltration, they have perished, and -this more especially in the case of those whose skeletons are composed -of aragonite. - -Carrying these facts with us, the next question is, What manner of -fossil remains should we expect to find in the Upper Laurentian rocks, -supposing that any such are therein preserved? The answer to this -question follows at once from the facts as to the succession of life -noticed above. Only the marine invertebrates have been traced as far -back as the oldest Cambrian, and only Worms, Sponges, and Protozoa -into the Huronian. We should therefore have no expectation of finding -remains of any vertebrate animals or of any of the land invertebrates; -and even allowing for the more favourable conditions, as compared -with the Huronian, evidenced by the great limestones and the abundant -carbon, we could scarcely expect anything higher than some of the -lower types of invertebrate life, such as Worms, Hydroids, Corals and -Protozoa. We have next to inquire what forms, possibly organic, have -actually been found, and what information we can derive from them as to -the beginnings of life. Since, however, such discoveries as have been -made have been the result of much labour and scientific skill brought -to bear on these old rocks, and are connected with the reputations of -several eminent men, now deceased, we may first refer shortly to the -history of the discovery of supposed fossils in the Laurentian rocks of -Canada. - -[Illustration: Fig. 25.--_Nature-print of an etched Specimen of Eozoon._ - -Showing the laminæ, a part of the natural margin, near which passes a -diagonal calcite vein, and at the upper right-hand corner, fragmental -material with casts of Archæospherinæ. The dark lines represent the -chambers filled with serpentine, the white the calcite wall.] - - - - - _THE HISTORY OF A DISCOVERY_ - - - - - VI - - _THE HISTORY OF A DISCOVERY_ - -When Mr. Logan, afterwards Sir William Logan, entered on the Geological -Survey of Canada, in 1840, he found that vast and little-explored -regions in the northern part of that country were occupied with -gneissic rocks, similar to the oldest gneisses of Scotland and -Scandinavia, and to which the name Azoic had been given by Murchison, -as rocks destitute of fossils, while they had been the "fundamental -granite" or ur-gneiss of most European geologists. They were -unquestionably below and more ancient than the oldest fossiliferous -Cambrian rocks both in Europe and North America, and geologists had for -the most part contented themselves with regarding them as primitive -rocks, destitute of any geological interest, much as some United States -geologists of the present day call them the "Archæan complex," a name -which the late Prof Dana has well characterized as a "term of despair." - -Logan was, however, a man not to be daunted by an unsolved problem, -even though the facts for its solution must be sought in a wilderness -known to few except adventurous trappers, hunters, and lumbermen; and -he soon learned that this ancient gneissic formation contained other -rocks beside gneiss, more especially thick and extensive limestones, -and that its beds seemed to have a definite arrangement, and could -be traced over great areas. He addressed himself, therefore, to -the problem of unravelling the tangled "complex," and with a few -hardy assistants, spent years in laboriously tracing its beds along -river courses and over mountains, and in mapping, in a manner never -previously attempted, its several members, designating at the same time -the whole by the term "Laurentian," because it constituted the mass -of the hills lying north of the St. Lawrence, called by old French -geographers the Laurentides, and separating the St. Lawrence Valley and -the region of the great lakes from Hudson's Bay and the Arctic Sea. In -this manner he laid a foundation, which still remains unshaken, for the -geology of the oldest rocks, and prepared the way for the discovery -of the forms afterward named Eozoon Canadense. At the same time Dr. -Sterry Hunt, the chemist of the Survey, was examining chemically the -rocks and minerals collected, and all Sir William's assistants were -instructed to search, more especially in the limestones, for anything -bearing the aspect of fossils. On the other hand. Dr. Carpenter was -independently pursuing his studies of the humbler inhabitants of the -modern ocean, and of the manner in which the pores of their skeletons -became infiltrated with mineral matter, and had kindly contributed -specimens to the collections of the writer in Canada. The discovery -of this most ancient fossil was thus not the chance picking up of a -rare and curious specimen, but the result of several combined lines of -laborious and skilful research. - -The following notice of the persons and incidents connected with its -discovery is taken from a previous publication of the writer, with only -a little alteration in terms to suit it to the present date. - -The first specimens of Eozoon ever procured, in so far as known, were -collected at Burgess, in Ontario, by a veteran Canadian mineralogist. -Dr. Wilson of Perth, and were sent to Sir William Logan as mineral -specimens. Their chief interest at that time lay in the fact that -certain laminæ of a dark green mineral present in the specimens -were found, on analysis by Dr. Hunt, to be composed of a new hydrous -silicate, allied to serpentine, and which he named loganite, but -which seems to be a mixture of different silicates. The form of this -mineral was not suspected to be of organic origin. Some years after, -in 1858, other specimens, differently mineralized with the minerals -serpentine and pyroxene, were found by Mr. J. McMullen, an explorer in -the service of the Geological Survey, in the limestone of the Grand -Calumet on the river Ottawa. These seem to have at once struck Sir W. -E. Logan as resembling the Silurian fossils known as _Stromatoporæ_, -or layer-corals, and at that time of quite uncertain nature, though -supposed to be allied to some kinds of modern corals. He showed them -to Mr. Billings, the palæontologist of the Survey, and to the writer, -with this suggestion, confirming it with the sagacious consideration -that inasmuch as the Ottawa and Burgess specimens were mineralized -by different substances, yet were alike in form, there was little -probability that they were merely mineral or concretionary. Mr. -Billings was naturally unwilling to risk his reputation in affirming -the organic nature of such specimens; and my own suggestion was that -they should be sliced, and examined microscopically; and that if -fossils, as they presented merely concentric laminæ and no cells, they -would probably prove to be protozoa rather than corals. A few slices -were accordingly made, but no definite structure could be detected. -Nevertheless, Sir William Logan took some of the specimens to the -meeting of the American Association at Springfield, in 1859, and -exhibited them as possibly Laurentian fossils; but the announcement was -evidently received with some incredulity. In 1862 they were exhibited -by Sir William to some geological friends in London, but he remarks -that "few seemed disposed to believe in their organic character, with -the exception of my friend Professor Ramsay." In 1863 the General -Report of the Geological Survey, summing up its work to that time, was -published, under the name of the "Geology of Canada," and in this, at -page 49, will be found two figures of one of the Calumet specimens, -here reproduced, and which, though unaccompanied with any specific -name or technical description, were referred to as probably Laurentian -fossils (Figs. 26 and 27). - -[Illustration: Fig. 26.--_Weathered Specimen of Eozoon from the Grand -Calumet._ (Collected by Mr. McMullen.)] - -[Illustration: Fig. 27.--_Cross Section of the Specimen represented in -Fig. 26._ - -The dark parts are the laminæ of calcareous matter converging to the -outer surface.] - -About this time Dr. Hunt happened to mention to me, in connection with -a paper on the mineralization of fossils which he was preparing, that -he proposed to notice the mode of preservation of certain fossil woods -and other things with which I was familiar, and that he would show me -the paper in proof, in order that he might have any suggestions that -occurred to me. On reading it, I observed, among other things, that -he alluded to the supposed Laurentian fossils, under the impression -that the organic part was represented by the serpentine or loganite, -and that the calcareous matter was the filling of the chambers. I took -exception to this, stating that though in the slices before examined -no structure was apparent, still my impression was that the calcareous -matter was the fossil, and the serpentine or loganite the filling. He -said: "In that case, would it not be well to re-examine the specimens, -and to try to discover which view is correct?" He mentioned at the same -time that Sir William had recently shown him some new and beautiful -specimens collected by Mr. Lowe, one of the explorers on the staff -of the Survey, from a third locality, at Grenville, on the Ottawa. -It was supposed that these might throw further light on the subject; -and accordingly Dr. Hunt suggested to Sir William to have additional -slices of these new specimens made by Mr. Weston, of the Survey, -whose skill as a preparer of these and other fossils has often done -good service to science. A few days thereafter, some slices were sent -to me, and were at once put under the microscope. I was delighted to -find in one of the first specimens examined, which happened to be cut -parallel to the laminæ, a beautiful group of tubuli penetrating one of -the calcite layers. Here was evidence, not only that the calcite layers -represented the true skeleton of the fossil, but also of its affinities -with the Foraminifera, whose tubulated supplemental skeleton, as -described and figured by Dr. Carpenter, and represented in specimens -in my collection presented by him, was evidently of the same type with -that preserved in the canals of these ancient fossils. Fig. 28 is an -accurate representation of the first seen group of canals penetrated by -serpentine. - -On showing the structures discovered to Sir William Logan, he entered -into the matter with enthusiasm, and had a great number of slices and -afterwards of decalcified specimens prepared, which were placed in my -hands for examination. - -[Illustration: Fig. 28.--_Group of Canals in the Supplemental Skeleton -of Eozoon._ - -Taken from the specimen in which they were first recognised. -(Magnified.)] - -[Illustration: Fig. 29.--_Canals of Eozoon, from same specimen,_ - -(Highly magnified.)] - -Feeling that the discovery was most important, but that it would be -met with determined scepticism on the part both of geologists and -biologists, I was not content with examining the typical specimens of -Eozoon, but had slices prepared of - -every variety of Laurentian limestone, of altered limestones from the -Cambrian and Silurian, and of serpentine marbles of all the varieties -furnished by our collections. These were examined with ordinary and -polarized light, and with every variety of illumination. Dr. Hunt, -on his part, undertook the chemical investigation of the various -associated minerals. An extensive series of notes and camera tracings -were made of all the appearances observed; and of some of the more -important structures beautiful drawings were executed by the late -Mr. H. S. Smith, the then palæontological draughtsman of the Survey. -The result of the whole investigation was a firm conviction that the -structure was organic and probably foraminiferal, and that it could be -distinguished from any merely mineral or crystalline forms occurring in -these or other limestones. - -At this stage of the matter, and after exhibiting to Sir William all -the characteristic appearances in comparison with such concretionary, -dendritic, and crystalline structures as most resembled them, and also -with the structure of recent and fossil Foraminifera, I suggested that -the further prosecution of the matter should be handed over to Mr. -Billings, as palæontologist of the Survey, and as our highest authority -on the fossils of the older rocks. - -[Illustration: Fig. 30.--_Casts of Canals of Eozoon, in Serpentine._ - -Decalcified and highly magnified.] - -[Illustration: Fig. 31.--_Group of finest Tubuli._ - -Highly magnified, from a micro-photograph.] - -I was engaged in other researches, and knew that no little labour -must be devoted to the work and to its publication, and that some -controversy might be expected. Mr. Billings, however, with his -characteristic caution and modesty, declined. His hands, he said, were -full of other work, and he had not specially studied the microscopic -appearances of Foraminifera or of mineral substances. It was finally -arranged that I should prepare a description of the fossil, which -Sir William would take to London, along with Dr. Hunt's notes, the -more important specimens, and lists of the structures observed in -each. Sir William was to submit the manuscript and specimens to Dr. -Carpenter, and also to Prof T. Rupert Jones, in the hope that these -eminent authorities would confirm our conclusions, and bring forward -new facts which I might have overlooked or been ignorant of Sir William -saw both gentlemen, who gave their testimony in favour of the organic -and foraminiferal character of the specimens; and Dr. Carpenter in -particular gave much attention to the subject, and worked out the -structure of the delicate tubulation of the surfaces of the laminæ or -cell-walls, which I had not distinguished previously, through a curious -accident as to specimens. Mr. Lowe had been sent back to the Ottawa -to explore, and just before Sir William's departure had sent in some -specimens from a new locality at Petite Nation, similar in general -appearance to those from Grenville, which Sir William took with him -unsliced to England. These showed in a perfect manner the tubuli of -the primary cell-wall, which I had in vain tried to resolve in the -Grenville specimens, and which I did not see until after they had been -detected by Dr. Carpenter in London. Dr. Carpenter thus contributed in -a very important manner to the perfecting of the investigations begun -in Canada, and on him fell the greater part of their illustration and -defence,[23] in so far as Great Britain is concerned. - -[Footnote 23: In papers by Dr. Carpenter, subsequently referred to. -Prof. Jones published an able exposition of the facts in the _Popular -Science Monthly_.] - -The immediate result was a composite paper in the _Proceedings of the -Geological Society_, by Sir W. E. Logan, Dr. Carpenter, Dr. Hunt, and -myself, in which the geology, palæontology, and mineralogy of _Eozoon -Canadense_ and its containing rocks were first given to the world.[24] -It cannot be wondered at that when geologists and palæontologists -were thus required to believe in the existence of organic remains in -rocks regarded as altogether Azoic and hopelessly barren of fossils, -and to carry back the dawn of life as far before those Cambrian rocks, -which were supposed to contain its first traces, as these are before -the middle period of the earth's life-history, some hesitation should -be felt. Further, the accurate appreciation of the evidence for such a -fossil as Eozoon required an amount of knowledge of minerals, of the -more humble types of animals, and of the conditions of mineralization -of organic remains, possessed by few even of professional geologists. -Thus Eozoon has met with some negative scepticism and positive -opposition--though the latter has been smaller in amount than might -have been anticipated, when we consider the novel and startling -character of the facts adduced. The most annoying element in the -discussion has consisted in the liability of observers, only partially -informed, to confound our specimens with things of very different -character, from which we had taken pains to distinguish them. - -[Footnote 24: In _Quarterly Journal of Geological Society_, vol. xxii.; -_Proc. Royal Society_, vol. xv.; _Intellectual Observer_, 1865; _Annals -and Magazine of Natural History_, 1874; and other papers and notices.] - -"The united thickness," says Sir William Logan, "of these three great -series, the Lower and Upper Laurentian and Huronian, may possibly far -surpass that of all succeeding rocks, from the base of the Palæozoic to -the present time. We are thus carried back to a period so far remote -that the appearance of the so-called Primordial fauna may be considered -a comparatively modern event."[25] So great a revolution of thought, -and this based on one fossil, of a character little recognisable by -geologists generally, might well tax the faith of a class of men -usually regarded as somewhat faithless and sceptical. Yet this new -extension of life has been very generally received, and has found -its way into text-books and popular treatises. Its opponents have -been under the necessity of inventing the most strange and incredible -pseudomorphoses of mineral substances to account for the facts. As -might have been expected, after the publication of the original paper, -other facts developed themselves. Mr. Vennor found other and scarcely -altered specimens closely allied to the Laurentian forms in the -Hastings series of Tudor, probably of Huronian age. Gümbel recognised -the organism in Laurentian rocks in Bavaria and elsewhere in Europe, -and discovered a new species in the Huronian of Bavaria.[26] Eozoon was -recognised in Laurentian limestones in Massachusetts[27] and New York, -and there has been a rapid growth of new facts increasing our knowledge -of Foraminifera and other humble animals in the succeeding Eozoic and -Palæozoic rocks. Special interest attaches to the discovery by Mr. -Vennor, and by Walcott and Matthew, to be mentioned in the sequel, -and tending to bridge over the interval between the Laurentian fossil -and those of the Lower Cambrian. Another fact, whose significance is -not to be over-estimated, is the recognition both by Dr. Carpenter -and myself of specimens in which the canals are occupied by dolomite -or by calcite like that of the organism itself I have made several -visits to the locality at Petite Nation originally discovered by -Mr. Lowe, in company with Dr. Carpenter, Dr. Bonney,[28] and other -skilled observers, and have very carefully studied all the facts with -reference to the mode of occurrence of the forms in the beds, and their -association with layers of fragmental Eozoon, and have found that these -are strictly in accordance with the theory that these old Laurentian -limestones are truly marine deposits, holding the remains of the sea -animals of their time. - -[Footnote 25: _Journal Geological Society_, February, 1865.] - -[Footnote 26: _Ueber das Vorkommen von Eozoon_, 1866.] - -[Footnote 27: By Mr. Bicknell at Newbury, and Mr. Burbank at -Chelmsford. The latter gentleman has since maintained that the -limestones at the latter place are not true beds; but his own -descriptions and figures lead to the belief that this is an error -of observation on his part. The Eozoon in the Chelmsford specimens -and in those of Warren, New York, is in small and rare fragments in -serpentinous limestone.] - -[Footnote 28: See an excellent account of one of these visits by Dr. -Bonney, _Geological Magazine_, 1895.] - -Eozoon is not, however, the only witness to the great fact of -Laurentian life, of which it is the most conspicuous exponent. In many -of the Laurentian limestones, mixed with innumerable fragments of -Eozoon, there are other fragments with traces of organic structure of -a different character. There are also casts in silicious matter which -seem to indicate smaller species of Foraminifera; and large laminated -forms, apparently organic, yet distinct from Eozoon. Some of these must -be noticed in the following pages. - -Other discoveries also are foreshadowed here. The microscope may -yet detect the true nature and affinities of some of the fragments -associated with Eozoon. Less altered portions of the Laurentian rocks -may be found, where even the vegetable matter may retain its organic -forms, and where fossils may be recognised by their external outlines -as well as by their internal structure. Thus the time may come when -the rocks now called Primordial shall not be held to be so in any -strict sense, and when swarming dynasties of Protozoa and other low -forms of life may be known as inhabitants of oceans vastly ancient as -compared with even the old Primordial seas. Who knows whether even the -land of the Laurentian time may not have been clothed with plants, -perhaps as much more strange and weird than those of the Devonian and -Carboniferous, as those of the latter are when compared with modern -forests? - - - - - _THE DAWN OF LIFE_ - - - - - VII - - _THE DAWN OF LIFE_ - - -In the Grenvillian system, as represented in the vicinity of the -Ottawa River, perfect specimens of Eozoon are found in one only of -the principal limestones there exposed, and in certain layers of that -limestone, and they are associated with concretions and grains of the -greenish mineral serpentine, which, as we shall see, has much to do -with their preservation. As exposed on broken surfaces, the specimens -consist of concentric layers of greenish serpentine and white calcite, -not, however, even or uniform, as in ordinary concretions having -concentric structure, but often approaching and uniting with each -other, so as to constitute wide flat chambers, and forming patches from -an inch to nearly a foot in diameter, while some of the larger patches -seem to coalesce or to become confluent. On weathered surfaces the -serpentine laminæ often become brown, owing to the rusting of the iron -contained in them, and project above the general surface, in this case -resembling very much the appearance of the layer-corals so plentiful in -some limestones of later date. - -The external forms of Eozoon are at first sight not very obvious, -as they adhere very closely to the containing rock; but the smaller -specimens, when entirely weathered out or disengaged by the solution of -the limestone in an acid, usually present the form of a broad inverted -cone, like some modern sponges or the broader turbinate fossil corals -(Fig. 32). The limestone having, like the other beds of the formation, -been much compressed and folded, the specimens of Eozoon are sometimes -crumpled in these folds or broken across by small cracks or faults, -which shift the laminæ slightly out of their places. The cracks thus -formed are also sometimes filled with a fibrous variety of serpentine, -known to mineralogists as chrysotile and popularly as "rock cotton" -or "asbestus." It is finely fibrous, and of a silky lustre, and must -have been deposited by water in the cracks and fissures formed by the -fracturing of the rock and the contained fossils, by movements taking -place after the whole was hardened. Accordingly these veins often cross -not only the rock, but also the serpentine and calcite layers of the -contained masses of Eozoon, without regard to the direction of their -laminæ, though sometimes they run parallel to the structure, the rock -having broken more easily in that direction. - -[Illustration: Fig. 32.--_Entire specimen of Eozoon, disengaged from -the matrix and showing its turbinate form, enclosed in the outline of a -larger specimen of similar form._ - -Both natural size, Côte St. Pierre. (Specimens in Peter Redpath -Museum.)] - -Bearing in mind these general points of material form and appearance, -we may now proceed to inquire as to the following points: (1) _The -structures visible in the specimens_; (2) _The manner in which they are -represented by different mineral substances, and how these are to be -accounted for_; (3) _The explanation of the whole on the supposition -that we are dealing with an animal fossil_. - -(1) In regard to the first of these questions, I may quote here, with -some slight alteration, from a recent memoir of my own[29]:-- - -[Footnote 29: _London Geological Magazine_, 1895.] - -In recent years I have been disposed to attach more importance than -formerly to the general form of Eozoon. The earlier examples studied -were, for the most part, imbedded in the limestone in such a manner -as to give little definite information as to external form; and at a -later date, when Sir William Logan employed one of his assistants, Mr. -Lowe, to quarry large specimens at Grenville and Côte St. Pierre, the -attempt was made to secure the most massive blocks possible, in order -to provide large slabs for showy museum specimens. - -[Illustration: Fig. 33.--_Weathered surface of Eozoon._ Showing -sections of two funnels or tubes with limiting walls, Côte St. Pierre.] - -More recently, when collections have been made from the eroded and -crumbling surfaces of the limestone in its wider exposures, it was -found that specimens of moderate size had been weathered out, and -could, either naturally or by treatment with acid, be entirely -separated from the matrix. Such specimens sometimes showed, either on -the surfaces or on the sides of "funnels" and tubes penetrating the -mass (Figs. 33, 34), a confluence of the laminæ, constituting a porous -cortex or limiting structure. Specimens of this kind were figured in -1888, and I was enabled to add to the characters of the species that -the original and proper form was "broadly turbinate with a depression -or cavity above, and occasionally with oscula or pits penetrating the -mass." The great flattened masses thus seemed to represent confluent or -overgrown individuals, often contorted by the folding of the enclosing -beds. - -[Illustration: Fig. 34.--_Section of the Base of a specimen of Eozoon._] - -This specimen shows an oscuilform, cylindrical funnel, cut in such -a manner as to show its _reticulated wall_ and the descent of the -laminæ toward it. Two-thirds of natural size. From a photograph. Col. -Carpenter, also in Redpath Museum. - -[This illustration (from Prof. Prestwich's "Geology," vol. ii. p. 21) -has been courteously lent by the Clarendon Press, Oxford.] - -There are also in well-preserved specimens certain constant properties -of the calcite and serpentine layers. The former are continuous, -and connected at intervals, so that if the silicious filling of -the chambers could be removed, the calcareous portion would form a -continuous skeleton, while the serpentine filling the chambers, when -the calcareous plates are dissolved out by an acid, forms a continuous -cast of the animal matter filling the chambers (Fig. 36). This cast -of the sarcodous material, when thus separated, is very uniformly -and beautifully mammillated on the surfaces of the laminæ, and this -tuberculation gradually passes upward into smaller chambers having -amœboid outlines, and finally into rounded chamberlets. It is also -a very constant point of structure that the lower laminæ of calcite -are thicker than those above, and have the canal-systems larger and -coarser. There is thus in the more perfect specimens a definite plan of -macroscopical structure (Fig. 35). - -[Illustration: Fig. 35.--_Structure of small specimen of Eozoon, -calcareous matter removed._] - -1. Natural size. 2. Acervuline cells of upper part. 3. Group of the -same coalescing into a lamina with tuberculated surface. 4. Laminæ with -tuberculated surfaces in section. (See also Fig. 36.) - -[Illustration: Fig. 36.--_Decalcified Eozoon, in section, slightly -enlarged._ Showing the character of the sarcodous laminæ now replaced -by Serpentine.] - -The normal mode of mineralization at Côte St. Pierre and Grenville is -that the laminæ of the test remain as calcite, while the chambers and -larger canals are filled with serpentine of a light green or olive -colour, and the finer tubuli are injected with dolomite. It may also -be observed that the serpentine in the larger cavities often shows a -banded structure, as if it had been deposited in successive coats, and -the canals are sometimes lined with a tubular film of serpentine, with -a core or axis of dolomite, which also extends into the finer tubuli of -the surfaces of the laminæ. This, on the theory of animal origin, is -the most perfect state of preservation, and it equals anything I have -seen in calcareous organisms of later periods. This state of perfection -is, however, naturally of infrequent occurrence. - -[Illustration: Fig. 37.--_Finest Tubuli filled with Dolomite -(magnified)._] - -The finer tubuli are rarely perfect or fully infiltrated. Even the -coarser canals are not infrequently imperfect, while the laminæ -themselves are sometimes crumpled, crushed, faulted, or penetrated with -veins of chrysotile or of calcite. In some instances the calcareous -laminæ are replaced by dolomite, in which case the canal-systems -are always imperfect or obsolete. The laminæ of the test itself are -also in some cases replaced by serpentine in a flocculent form. At -the opposite extreme are specimens, or portions of specimens, in -which the chambers are obliterated by pressure, or occupied only -with calcite. In such cases the general structure is entirely lost -to view, and scarcely appears in weathering. It can be detected only -by microscopic examination of slices, in parts where the granular -structure or the tubulation of the calcite layers has been preserved. -All palæontologists who have studied silicified fossils in the older -rocks are familiar with such appearances. - -[Illustration: Fig. 38.--_Plan of arrangement of Canals in Lamina of -Eozoon._] - -It has been alleged by Möbius and others that the canal-systems and -tubes present no organic regularity. This difficulty, however, arises -solely from imperfect specimens or inattention to the necessary results -of slicing any system of ramifying canals. In Eozoon the canals form -ramifying groups in the middle planes of the laminæ, and proceed at -first almost horizontally, dividing into smaller branches, which -ultimately give off brushes of minute tubuli running nearly at right -angles to the surfaces of the lamina, and forming the extremely fine -tubulation which Dr. Carpenter regarded as the proper wall (Figs. 38, -39). - -[Illustration: Fig. 39.--_Cross section of minute Tubuli, about 5 -microms in diameter (magnified)._] - -In my earlier description I did not distinguish this from the -canal-system, with which its tubuli are inwardly continuous. Dr. -Carpenter, however, understood this arrangement, and has represented -it in his figures[30] (see also Fig. 28). It is evident that in a -structure like this a transverse or oblique section will show truncated -portions of the larger tubes apparently intermixed with others much -finer and not continuous with them, except very rarely. Good specimens -and many slices and decalcified portions are necessary to understand -the arrangement This consideration alone, I think, entirely invalidates -the criticisms of Möbius, and renders his large and costly figures of -little value, though his memoir is, as I have elsewhere shown, liable -to other and fatal objections.[31] - -[Footnote 30: "Ann. and Mag. Nat. Hist.," ser. 4, xiii., p. 456, figs. -3, 4.] - -[Footnote 31: "Museum Memoir," pp. 50 _et seq._] - -It has been pretended that the veins of chrysotile, when parallel -to the laminæ, cannot be distinguished from the minute tubuli -terminating on the surfaces of the laminæ. I feel confident, however, -that no microscopist who has seen both, under proper conditions of -preservation and study, could confound them. The fibres of chrysotile -are closely appressed parallel prisms, with the optical properties of -serpentine. The best preserved specimens of the "proper wall" contain -no serpentine, but are composed of calcite with extremely minute -parallel cylinders of dolomite about five to ten microms. in diameter, -and separated by spaces greater than their own diameter (Figs. 40, 41). -In the rare cases where the cylinders are filled with serpentine, they -are, of course, still more distinct and beautiful. At the same time, -I do not doubt that observers who have not seen the true tubulation -may have been misled by chrysotile veins when these fringe the laminæ. -Möbius, for instance, figures the true and false structure as if they -were the same. - -[Illustration: Fig. 40.--_Cross section of similar Tubuli to those in -Fig. 39, more highly magnified, and showing granular character of the -test._ - -(From camera tracings.)] - -[Illustration: Fig. 41.--_Comparison of Tubulate Wall and Prisms of -Chrysotile in perspective._] - -[Illustration: _Canals of Eozoon._ (After Möbius.)] - -[Illustration: _Finer Canals of Eozoon._ (After Möbius.)] - -[Illustration: _Canals of modern Calcarina._ (After Carpenter.)] - -[Illustration: _Canals and Tubule of Tertiary Nummulina._ (After -Möbius.)] - -Fig. 42. - -Figures selected from Möbius, to show the resemblance of structures of -Eozoon to those of modern Foraminifera. - -Protest should here be made against that mode of treating ancient -fossils which regards the most obscure or defaced specimens as typical, -and those better preserved as mere accidents, of mineral structure. In -Tertiary Nummulites injected with glauconite it is rare to find the -tubuli perfectly filled, except in tufts here and there; yet no one -doubts that these patches represent a continuous structure. - -I have remarked on previous occasions that the calcite constituting the -laminæ of Eozoon often has a minutely granular appearance, different -from that of the surrounding limestone. Under a high power it resolves -itself into extremely minute dots or flocculi, somewhat uniformly -diffused. Whether these dots are particles of carbon, iron, apatite, or -silicious matter, or the remains of a porous structure, I do not know; -but similar appearances occur in the calcareous fossils contained in -altered limestones of later date. Wherever they occur in crystalline -limestones, supposed to be organic, the microscopist should examine -them with care. I have sometimes by this appearance detected fragments -of Eozoon which afterward revealed their canals. - -(2) The second question requires us to consider the nature and -origin of the substances constituting the specimens. Reference has -already been made to these in our fifth chapter, but they may be -more particularly noticed here in connection with the forms as above -described. - -The calcareous laminæ are usually composed of clear translucent -calcite or calcium carbonate, though, as in the case of many later -fossils, sometimes replaced by dolomite. It often has the fine granular -appearance above referred to, but is nearly always crystalline, and -traversed by cleavage planes visible under the microscope.[32] This -crystalline structure, as every student of fossils knows, is very -common in calcareous fossils of all geological ages. In the thicker -laminæ the canals traversing them and branching out in their substance -are usually visible under a low power, except when they are filled with -calcite similar to that of the laminæ themselves. In this case they -can be seen only by very careful management of an oblique and subdued -light. When occupied with serpentine, this presents, in a thin slice -under transmitted light, a yellowish or brownish colour, and in a -specimen decalcified with an acid an opaque white appearance. In some -of the larger threads of serpentine, as already stated, this mineral -forms a thin outer cylinder with a core of calcite or dolomite within; -but this appearance is not common. Here and there, especially in the -lower layers, a portion of a tube is filled with the harder mineral -pyroxene, which is in some respects similar to serpentine, except -that it contains lime as well as magnesia, and is destitute of water -as an ingredient The finer tubuli into which the canals ramify are -most usually filled with dolomite or magnesian limestone, which has -a glossy appearance and higher lustre than the surrounding calcite, -and so may be distinguished even in a transparent slice; but these -fine dolomite threads are best seen when the surface of a slice is -treated with a dilute acid in the cold, in which circumstances the -calcite is dissolved, while the dolomite remains as tufts of delicate -cylindrical hairs, presenting often a very beautiful appearance under -the microscope. Thus, as in many other fossils, what are supposed to -have been tubes and tubuli are found not empty, but filled with matter -even harder and more resisting than the shell itself. - -[Footnote 32: Especially when the specimen has been heated or jarred in -the process of grinding or polishing.] - -Serpentine is a mineral which has been produced in different ways. -Some igneous or volcanic rocks consist largely of compounds of silica -and magnesia (olivine, etc.). When these rocks have become cold and -are exposed to the action of water, they sometimes absorb this and -become hydrated, thus passing into a kind of serpentine. When such -rocks are pulverized and dispersed as volcanic ash, this falling into -the sea may be there hydrated, and may form serpentinous layers, or in -a fine paste or in solution may pass into the pores and cavities of -shells and other organic things, acting, as we have seen, in the same -manner with ordinary glauconite. In like manner serpentine of this -origin may form nodules or grains in limestones, in consequence of its -particles being aggregated together by concretionary attraction. We -have already seen that some comparatively modern so-called glauconites -are essentially of the nature of serpentine, and we know that in the -old Laurentian sea, salts of magnesia and magnesian minerals were -abundant, so that serpentinous minerals might play a greater part than -they do in the modern seas. Loganite, the mineralizing substance of -the Burgess Eozoon, is different from serpentine, yet closely allied -to the glauconites. The presence of pyroxene may be explained in a -similar way. It is a frequent constituent of bedded volcanic rocks -and of volcanic ashes, and beds of it occur in the Grenville series -which once, no doubt, were ash-beds. Layers of it also occasionally -occur from a similar cause in the limestone, and crystals of it have -been deposited by water in the veins passing through the limestones -and schists. Dr. Johnston-Lavis has described in the July number of -the _Geological Magazine_ for 1895 the aqueous deposition at ordinary -temperature of crystals of pyroxene and hornblende, in cavities and -crevices of bones included in an ash-bed of recent date, and in -presence of calcite, apatite, and fluoride of calcium, as in the -Grenville series. This is a modern instance analogous to that suggested -above. Hence all these minerals filling the cavities and canals of -Eozoon may have been deposited by water at ordinary temperatures, and -have no connection with the alteration to which the beds have been -subsequently subjected. - -I may add here that a Tertiary glauconite from the Calcaire Grossier -of Paris analysed by Berthier[33] is essentially a serpentine composed -of silicate of iron and magnesia, that Loganite as analysed by Hunt -contains thirty-one per cent, of magnesia, and that Hoskins has -shown[34] that modern glauconites often contain large proportions of -magnesia and equivalent bases. - -[Footnote 33: Beudant, _Mineralogie_, xi. 178.] - -[Footnote 34: _Geological Magazine_, July, 1895.] - -It is also to be observed that independently of volcanic debris the -reports of the _Challenger_ expedition show that in the deep seas -the decay of organic matter causes an alkaline condition of the -sediments leading to the formation of alkaline silicates, while the -presence of decaying volcanic dust furnishes the basis, whether of -iron, alumina, or magnesia, necessary for the making up of glauconite. -I have also suggested that the assimilation by Protozoa making -calcareous skeletons, of the matter of Diatoms or humble plants having -soluble silica in their organization or of silicious Protozoa, and -sponge germs, must set free much soluble silica as a rejected or -excrementitious matter which may contribute to the same result. - -It is much more likely that the serpentine of the Laurentian limestones -was produced in these ways than that it resulted from the hydration -of magnesian minerals after the rock was consolidated. In the former -case it would be in the most favourable conditions for mineralizing -organisms as glauconites do in the modern seas. In the latter it would -cause disturbances and changes of volume of which we have no evidence. - -We thus find that the chemistry of the modern seas and that relating to -the preservation of fossils of various ages by silicious infiltrations -lends great probability to the belief that serpentine played this -role in the oldest seas, though it would seem that dolomite was more -suitable to the filling of the extremities of the minute tubes and -their finer terminations.[35] - -[Footnote 35: I have shown also that in the limestone containing Eozoon -we find layers holding concretions of serpentine alternating with -others holding crystals of dolomite, as if there were at some times -conditions favourable to the deposition of silicate of magnesia, and at -others to that of the carbonate.] - -[Illustration: Fig. 43.--Stromatocerium rugosum, Hall, Ordovician.] - -(3) Our third question leads to the inquiry in what modern or ancient -marine animals we can find structures akin to those of our supposed -Laurentian fossil. The first analogy which suggested itself to Sir W. -Logan, and a very natural one, was that to the so-called layer-corals -(Figs. 43 to 45) that abound in the Silurian, Ordovician, and Cambrian -rocks, and which though undoubtedly fossil animals, have proved very -difficult to interpret or to assign to any known group. At first -vaguely associated with the true corals, they were subsequently -regarded as probably of more simple character, and as gigantic -Protozoa; and later strong reasons have been assigned for giving them -an intermediate place, as allied to those curious communities of humble -animals possessing simple stomachs and prehensile tentacles (Hydroids) -which form some of the simpler corals (Millepores, etc.), and the -crusts (Hydractiniæ) which cover dead shells and other bodies in the -sea. When examined microscopically, however, they differ very much -among themselves, and it may be that some of them were Hydroids and -some Protozoa. - -[Illustration: Fig. 44.--_Structures of Stromatopora._ - -(_a_) Portion of oblique section, (_b_) Wall with pores, and coated -with crystals of quartz, (_c_) Thickened portion of wall with canals, -(_d_) Laminæ and pillars.] - -[Illustration: Fig. 45.--_Tubular Structure of Cœnostroma, Silurian._] - -The oldest that we at present know, and consequently the nearest in -time to Eozoon, impress us rather with the latter affinity. They -are the fossils of the genus Cryptozoon of Hall (Fig. 7[36]), which -form great masses filling certain beds of Upper Cambrian age, and -which, when sliced and studied microscopically, are found to consist -of concentric thin laminæ filled in between with a porous mass of -calcareous matter penetrated by an infinity of tortuous tubes. Forms of -this kind have been traced downward into pre-Cambrian beds in Colorado, -and as we shall find in New Brunswick, into the Upper Laurentian itself. - -[Footnote 36: See Figs. 7 and 7a, pp. 37, 38; also Fig. 8 and -Microscopic slice, Fig. 59, at end.] - -They present, however, structural differences from Eozoon, which -rather conforms to the arrangements found in some Protozoa of smaller -size, and which, under the name of Foraminifera, have abounded in all -geological periods, and are excessively abundant in the modern ocean. -They may be defined as animals composed of a soft and apparently -homogeneous animal jelly known as protoplasm or sarcode. When carefully -examined, however, it is found to have a granular texture and to be -divisible into two layers, an outer and an inner, while it possesses -a little hollow vessel capable of expanding and absorbing the liquid -matter of the enclosing protoplasm, and of contracting so as to expel -its contents. This seems to be the only organ of circulation and -excretion. There are, however, small cells or reproductive bodies in -the interior, varying in number, size, and development in different -forms. The most remarkable property of these creatures is that of -stretching out from the surface of the body threads or projections of -the protoplasm,[37] often of considerable length, and which serve at -once as organs of locomotion and prehension. - -[Footnote 37: Known as Pseudopodia.] - -[Illustration: _Amœba._] - -[Illustration: _Actinophrys._] - -From original sketches. - -[Illustration: _Biloculina._ A many-chambered Foraminifer. Magnified as -a transparent object.] - -[Illustration: _Polystomella._ A spiral Foraminifer. Magnified as an -opaque object.] - -Fig. 46.--Recent Protozoa. - -These creatures are in some respects the simplest of animals, yet -in other respects they present strange complexities. This is more -especially evident in their tests or coverings, made for the most part -of limestone or calcium carbonate, but sometimes of grains of fine -sand cemented together. These coverings are always perforated with at -least one orifice for the emission of the thread-like processes or -pseudopods, and often with a vast number of small pores for the same -purpose. Sometimes the test or shell is smooth, sometimes beautifully -sculptured externally. Sometimes it consists of a single chamber like -a ball or vase. More often, as the animals increase in size, they -form additional chambers, and the body thus becomes divided into -lobes connected with each other by necks passing through orifices in -the partitions. The chambers are arranged in rows or in spirals, and -in other ways, giving a vast variety of forms, often presenting the -most beautiful patterns executed in the purest white marble, and the -ornamental parts constitute thickenings of the walls giving greater -strength, and are penetrated with microscopic canals communicating with -the soft substance of the animal. - -These creatures abound in all parts of the ocean, from the surface -to the greatest depths. The Foraminifera have also existed from -the earliest geological times, and in all the long ages of the -earth's history seem to have retained the same structures and even -ornamentation; so that species from very old geological formations -are often scarcely distinguishable from those now living, and must -have played precisely the same parts in the system of nature. One of -these functions is that of accumulating great thicknesses of calcareous -matter in the sea-bottom. - -The manner in which such accumulation takes place we learn from what -is now going on in the ocean, more especially from the result of the -recent deep-sea dredging expeditions. The Foraminifera are vastly -numerous, both near the surface and at the bottom of the sea, and -multiply rapidly; and as successive generations die, their shells -accumulate on the ocean bed, or are swept by currents into banks, and -thus in process of time constitute thick beds of white chalky material, -which may eventually be hardened into limestone. This process is now -depositing a great thickness of white ooze in the bottom of the ocean; -and in times past it has produced such vast thicknesses of calcareous -matter as the chalk and the nummulitic limestone of Europe and the -orbitoidal limestone of America. The chalk, which alone attains a -maximum thickness of 1,000 feet, and, according to Lyell, can be traced -across Europe for 1,100 geographical miles, may be said to be entirely -composed of shells of Foraminifera imbedded in a paste of still more -minute calcareous bodies, the Coccoliths, which are probably products -of marine vegetable life, if not of some animal organism still simpler -than the Foraminifera. - -There are, however, some sessile examples of these animals which -attain to larger dimensions than the free and locomotive forms. As an -example of these we may take the _Polytrema_, which forms little hard -red lumps on West Indian corals. Such a creature, beginning life as a -little round spot of protoplasm, almost invisible, and protected with a -little dome of carbonate of lime for the extension of its pseudopods as -it grows in size, adds chamber to chamber in successive tiers till it -assumes an appreciable size, all the chambers communicating with each -other, while the outer ones are perforated with pores for extension of -the pseudopods. In one form (_Carpenteria_) the same end is secured by -leaving an open space in the middle of the conical mass like the crater -of a small volcano. It is with these larger and sessile forms that -we must compare Eozoon, though some of its minute structures rather -resemble those of some smaller types. - -All the creatures referred to above, notwithstanding the differences -in their skeletons, resemble each other very closely in their soft -parts, and come under the general name of Foraminifera, a name -having reference to the openings by which the animal matter within -communicates with the water without, for nutrition and respiration. -Such creatures may be regarded as the simplest and most ready media -for the conversion of vegetable matter into animal tissues, and their -functions are almost entirely limited to those of nutrition. Hence it -is likely that they will be able to appear in the most gigantic forms -under such conditions as afford them the greatest amount of pabulum -for the nourishment of their soft parts and for their skeletons. There -is reason to believe, for example, that the occurrence, both in the -chalk and the deep-sea mud, of immense quantities of the minute oval -bodies known as Coccoliths along with Foraminifera, is not accidental. -The Coccoliths appear to be grains of calcareous matter formed in -minute plants adapted to a deep-sea habitat; and these, along with -the vegetable and animal debris constantly being derived from the -death of the living things at the surface, and falling to the bottom, -afford the material both of sarcode and shell. Now if the Laurentian -graphite represents an exuberance of vegetable growth in those old seas -proportionate to the great supplies of carbonic acid in the atmosphere -and in the waters, and if the Eozoic ocean was even better supplied -with carbonate of lime than those Silurian seas whose vast limestones -bear testimony to their richness in such material, we can easily -imagine that the conditions may have been more favourable to a creature -like Eozoon than those of any other period of geological time. - -Growing, as Eozoon may be supposed to have done, on the floor of the -ocean, and covering wide patches with more or less irregular masses, -it must have thrown up from its whole surface its pseudopods to seize -whatever floating particles of food the waters carried over it There -is also reason to believe, from the outline of certain specimens, that -it often grew upward in inverted, conical, or club-shaped forms, and -that only the broader patches were penetrated by the tubes or oscula -already mentioned, admitting the sea-water deeply into the substance of -the masses. In this way its growth might be rapid and continuous; but -it does not seem to have possessed the power of growing indefinitely -by new and living layers covering those that had died, in the manner -of some corals. Its life seems to have had a definite termination, and -when that was reached, an entirely new colony had to be commenced. -In this it had more affinity with the Foraminifera, as we now know -them, than with the corals, though practically it had the same power -with the coral polyps of accumulating limestone in the sea-bottom, a -power indeed still possessed by its foraminiferal successors. In the -case of coral limestones, we know that a large proportion of these -consist, not of continuous reefs, but of fragments of coral mixed with -other calcareous organisms, spread usually by waves and currents in -continuous beds over the sea-bottom. In like manner we find in the -limestones containing Eozoon, layers of fragmental matter which shows -in places the characteristic structures, and which evidently represents -the debris swept from the Eozoon masses and reefs by the action of -the waves. With this fragmental matter small rounded organisms to be -noticed in the sequel occur; and while they may be distinct animals -resembling the smaller modern species, they may also be the fry of -Eozoon, or small portions of its acervuline upper surface floated off -in a living state, and possibly capable of living independently and of -founding new colonies. - -[Illustration: Fig. 47.--_Slice of Limestone (magnified),_ - -(_a_) Fragment of Eozoon with canals, (_b_) Fragments of granular -calcite, probably organic, (_c_) Structureless calcite with cleavage -lines (Côte St. Pierre).] - -It is only by a somewhat wild poetical licence that Eozoon has been -represented as a "kind of enormous composite animal stretching from the -shores of Labrador to Lake Superior, and thence northward and southward -to an unknown distance, and forming masses 1,500 feet in depth." We may -discuss by-and-by the question of the composite nature of masses of -Eozoon, and we see in the corals evidence of the great size to which -composite animals of a higher grade can attain. In the case of Eozoon -we must imagine an ocean floor more uniform and level than that now -existing. On this the organism would establish itself in spots and -patches. These might finally become confluent over large areas, just -as massive corals do. As individual masses attained maturity and died, -their pores would be filled up with limestone or silicious deposits, -and thus could form a solid basis for new generations, and in this way -limestone to an indefinite extent might be produced. Further, wherever -such masses were high enough to be attacked by the breakers, or where -portions of the sea-bottom were elevated, the more fragile parts of the -surface would be broken up and scattered widely in beds of fragments -over the bottom of the sea, while here and there beds of mud or sand -or of volcanic debris would be deposited over the living or dead -organic mass, and would form the layers of gneiss and other schistose -rocks interstratified with the Laurentian limestone. In this way, in -short, Eozoon would perform a function combining that which corals and -Foraminifera perform in the modern seas; forming both reef limestones -and extensive chalky beds, and probably living both in the shallow and -the deeper parts of the ocean. If in connection with this we consider -the rapidity with which the soft, simple, and almost structureless -sarcode of these Protozoa can be built up, and the probability that -they were more abundantly supplied with food, both for nourishing their -soft parts and skeletons, than any similar creatures in later times, we -can readily understand the great volume and extent of the Laurentian -limestones which they aided in producing. I say aided in producing, -because I would not desire to commit myself to the doctrine that the -Laurentian limestones are wholly of this origin. There may have been -other animal limestone-builders than Eozoon, and there may have been -limestones formed by plants like the modern Nullipores or by merely -mineral deposition. - -Its relations to modern animals of its type have been very clearly -defined by Dr. Carpenter. In the structure of its proper wall and its -fine parallel perforations, it resembles the _Nummulites_ and their -allies (Figs. 48, 49); and the organism may therefore be regarded as -an aberrant member of the Nummuline group, which affords some of the -largest and most widely distributed of the fossil Foraminifera. This -resemblance may be seen in Fig. 48. - -[Illustration: Fig. 48.--_Section of a Nummulite, from Eocene Limestone -of Syria._ - -Showing chambers, tubuli, and canals. Compare this and Fig. 49 with -Figs. 28 and 29.] - -[Illustration: Fig. 49.--_Portion of Shell of Calcarina._ - -Magnified, after Carpenter, (_a_) Cells. (_b_) Original cell-wall with -tubuli. (_c_) Supplementary skeleton with canals.] - -To the Nummulites it also conforms in its tendency to form a -supplemental or intermediate skeleton with canals, though the canals -themselves in their arrangement more nearly resemble Calcarina, which -is represented in Fig. 49. In its superposition of many layers, and in -its tendency to a heaped-up or acervuline irregular growth it resembles -_Carpenteria_, _Polytrema_ and _Tinoporus_, forms of a different group -in so far as shell-structure is concerned. The large and curious sandy -Foraminifer from the Pacific dredged by Alexander Agassiz, and named -by Goës, _Neusina Agassizi_, may also be mentioned as presenting some -points of resemblance.[38] It may thus be regarded as a composite -type, combining peculiarities now observed in two groups, or it may be -regarded as a representative in the Nummuline series of Polytrema and -Tinoporus in the Rotaline series. At the time when Dr. Carpenter stated -these affinities, it might be objected that Foraminifera of these -families are in the main found in the Modern and Tertiary periods. Dr. -Carpenter has since shown that the curious oval Foraminifer called -_Fusulina_, found in the coal formation, is in like manner allied to -both Nummulites and Rotalines; and still more recently Mr. Brady has -discovered a true Nummulite in the Lower Carboniferous of Belgium. This -group being now fairly brought down to the Palæozoic, we may hope -finally to trace it back to the Primordial, and thus to bring it still -nearer to Eozoon in time. - -[Footnote 38: _Bulletin Mus. Comp. Zoology_, vol. xxiii., No. 5, Dec., -1892.] - -Though Eozoon was probably not the only animal of the Laurentian seas, -yet it was in all likelihood the most conspicuous and important as -a collector of calcareous matter, filling the same place afterwards -occupied by the reef-building corals. Though probably less efficient -than these as a constructor of solid limestones, from its less -permanent and continuous growth, it formed wide floors and patches -on the sea-bottom, and when these were broken up vast quantities of -limestone were formed from their debris. It must also be borne in -mind that Eozoon was not everywhere infiltrated with serpentine or -other silicious minerals; quantities of its substance were merely -filled with carbonate of lime, resembling the chamber-wall so closely -that it is nearly impossible to make out the difference, and thus is -likely to pass altogether unobserved by collectors, and to baffle -even the microscopist. Although therefore the layers which contain -well-characterized Eozoon are few and far between, there is reason to -believe that in the composition of the limestones of the Laurentian it -bore no small part; and as these limestones are some of them several -hundreds of feet in thickness, and extend over vast areas, Eozoon -may be supposed to have been as efficient a world-builder as the -Stromatoporæ of the Silurian and Devonian, the Globigerinæ and their -allies in the chalk, or the Nummulites and Miliolites in the Eocene. It -is a remarkable illustration of the constancy of natural causes and of -the persistence of animal types, that these humble Protozoans, which -began to secrete calcareous matter in the Laurentian period, have been -continuing their work in the ocean through all the geological ages, -and are still busy in accumulating those chalky muds with which recent -dredging operations in the deep sea have made us so familiar. - -[Illustration: Fig. 50.--_Figures of Archæospherinæ._ - -(1) Specimen with tubulated wall. (2 to 5) Casts in serpentine, Côte -St. Pierre and Long Lake] - - - - - _CONTEMPORARIES OF EOZOON_ - - - - - VIII - - _CONTEMPORARIES OF EOZOON_ - - -The name Eozoon, or Dawn-animal, raises the question whether we -shall ever know any earlier representative of animal life. Here I -think it necessary to explain that in suggesting the name Eozoon for -the earliest fossil, and Eozoic for the formation in which it is -contained, I had no intention to affirm that there may not have been -precursors of the Dawn-animal. By the similar term. Eocene, Lyell -did not mean to affirm that there may not have been modern types in -the preceding geological periods: and so the dawn of animal life may -have had its grey or rosy breaking at a time long anterior to that in -which Eozoon built its marble reefs. When the fossils of this early -auroral time shall be found, it will not be hard to invent appropriate -names for them. There are, however, two reasons that give propriety -to the name in the present state of our knowledge. One is, that the -Laurentian rocks are absolutely the oldest that have yet come under -the notice of geologists, and at the present moment it seems extremely -improbable that any older sediments exist, at least in a condition to -be recognised as such. The other is that Eozoon, as a member of the -group Protozoa, of gigantic size and comprehensive type, and oceanic in -its habitat, is as likely as any other creature that can be imagined -to have been the first representative of animal life on our planet. -Vegetable life may have preceded it, nay probably did so by at least -one great creative æon, and may have accumulated previous stores of -organic matter; but if any older forms of animal life existed, it is -certain at least that they cannot have belonged to much simpler or more -comprehensive types. It is also to be observed that such forms of life, -if they did exist, may have been naked protozoa, which may have left no -sign of their existence except a minute trace of carbonaceous matter, -and perhaps not even this. - -But if we do not know, and perhaps are not likely to know, any -animals older than Eozoon, may we not find traces of some of its -contemporaries, either in the Eozoon limestones themselves, or other -rocks associated with them? Here we must admit that a deep-sea -Foraminiferal limestone may give a very imperfect indication of the -fauna of its time. A dredger who should have no other information as -to the existing population of the world, except what he could gather -from the deposits formed under several hundred fathoms of water, -would necessarily have very inadequate conceptions of the matter. In -like manner a geologist who should have no other information as to -the animal life of the Mesozoic ages than that furnished by some of -the thick beds of white chalk, might imagine that he had reached a -period when the simplest kinds of protozoa predominated over all other -forms of life; but this impression would at once be corrected by the -examination of other deposits of the same age: so our inferences as to -the life of the Laurentian from the contents of its oceanic limestones -may be very imperfect, and it may yet yield other and various fossils. -Its possibilities are, however, limited by the fact that before we -reach this great depth in the earth's crust, we have already left -behind in much newer formations all traces of animal life except a -few of the lower forms of aquatic invertebrates; so that we are not -surprised to find only a limited number of living things, and those of -very low type. Do we then know in the Laurentian even a few distinct -species, or is our view limited altogether to Eozoon Canadense? In -answering this question, we must bear in mind that the Laurentian -itself was of vast duration, and that important changes of life may -have taken place even between the deposition of the Eozoon limestones -and that of those rocks in which we find the comparatively rich fauna -of the Primordial age. This subject was discussed by the writer as -early as 1865, and I may repeat here what could be said in relation to -it at that time:-- - -"In connection with these remarkable remains, it appeared desirable to -ascertain, if possible, what share these or other organic structures -may have had in the accumulation of the limestones of the Laurentian -series. Specimens were therefore selected by Sir W. E. Logan, and -slices were prepared under his direction. On microscopic examination, -a number of these were found to exhibit merely a granular aggregation -of crystals, occasionally with particles of graphite and other foreign -minerals, or a laminated mixture of calcareous and other matters, in -the manner of some more modern sedimentary limestones. Others, however, -were evidently made up almost entirely of fragments of Eozoon, or of -mixtures of these with other calcareous and carbonaceous fragments -which afford more or less evidence of organic origin. The contents of -these organic limestones may be considered under the following heads:-- - - 1. Remains of Eozoon. - - 2. Other calcareous bodies, probably organic. - - 3. Objects imbedded in the serpentine. - - 4. Carbonaceous matters. - -"(1) The more perfect individuals of Eozoon do not constitute the mass -of any of the larger specimens in our collections; but considerable -portions of some of them are made up of material of similar minute -structure, destitute of lamination, and irregularly arranged. Some of -this material gives the impression that there may have been organisms -similar to Eozoon, but growing in an irregular or acervuline manner -without lamination. Of this, however, I cannot be certain; and, on the -other hand, there is distinct evidence of the aggregation of fragments -of Eozoon in some of these specimens. In some they constitute the -greater part of the mass. In others they are imbedded in calcareous -matter of a different character, or in serpentine or granular pyroxene. -In most of the specimens the cells of the fossils are more or less -filled with these minerals; and in some instances it would appear that -the calcareous matter of fragments of Eozoon has been in part replaced -by serpentine." - -[I may add here that in the limestone at Côte St. Pierre there are in -some of the beds successive laminæ with grains of serpentine and others -with crystals of dolomite, and that both contain fragments of Eozoon. -It thus seems as if the magnesia associated with the limestone, at some -stages of deposition took the form of silicate, and in others that of -carbonate. I may also observe here that I have detected fragments of -Eozoon in Laurentian limestone from New Brunswick, from Chelmsford in -Massachusetts, from Warren County, New York, from Brazil, and from the -Alps.] - -"(2) Intermixed with the fragments of Eozoon above referred to are -other calcareous matters apparently fragmentary. They are of various -angular and rounded forms, and present several kinds of structure. The -most frequent of these is a strong lamination varying in direction -according to the position of the fragments, but corresponding, as -far as can be ascertained, with the diagonal of the rhombohedral -cleavage. This structure, though crystalline, is highly characteristic -of crinoidal remains when preserved in altered limestones. The more -dense parts of Eozoon, destitute of tubuli, also sometimes show -this structure, though less distinctly. Other fragments are compact -and structureless, or show only a fine granular appearance; and -these sometimes include grains, patches, or fibres of graphite. In -Cambro-Silurian limestones, fragments of corals and shells which have -been partially infiltrated with bituminous matter, show a structure -like this. On comparison with altered organic limestones of the -Cambro-Silurian system, these appearances would indicate that, in -addition to the debris of Eozoon, other calcareous structures, more -like those of crinoids, corals, and shells, have contributed to the -formation of the Laurentian limestones. - -"(3) In the hydrous silicate (Loganite) filling the chambers of a -large specimen of Eozoon from Burgess, there are numerous small pieces -of foreign matter; and the silicate itself is laminated, indicating -its sedimentary nature. Some of the included fragments appear to be -carbonaceous, others calcareous; but no distinct organic structure -can be detected in them. There are, however, in the Loganite, many -minute silicious grains of a bright green colour, resembling green-sand -concretions; and the manner In which these are occasionally arranged -in lines and groups suggests the supposition that they may possibly -be casts of the interior of minute Foraminiferal shells. They may, -however, be concretionary in their origin (Fig. 51). - -[Illustration: Fig. 51.--Archæospherinæ from Burgess Eozoon. Grains -included in Loganite. - -(Magnified.)] - -"(4) In some of the Laurentian limestones submitted to me by Sir W. E. -Logan, and in others from Arnprior on the Ottawa, there are fibres and -granules of carbonaceous matter which do not conform to the crystalline -structure, and present appearances quite similar to those which in -more modern limestones result from the decomposition of the algæ, etc. -Though retaining mere traces of organic structure, little doubt would -be entertained as to their vegetable origin if they were found in -fossiliferous limestones. In limestones of Upper Laurentian age, near -St. John, New Brunswick, more distinct fibres occur, and associated -with these beds Matthew has found what seem to be spicules of sponges, -some simple and others hexactinelled like those of Protospongia of the -Cambrian. - -Though the abundance and wide distribution of Eozoon, and the important -part it seems to have acted in the accumulation of limestone, indicate -that it was one of the most prevalent forms of animal existence -in the seas of the Laurentian period, the non-existence of other -organic beings is not implied. On the contrary, independently of the -indications afforded by the limestones themselves, it is evident that -in order to the existence and growth of these large Rhizopods, the -waters must have swarmed with more minute animal or vegetable organisms -on which they could subsist. On the other hand, though this is a less -certain inference, the dense calcareous skeleton of Eozoon may indicate -that it also was liable to the attacks of animal enemies. It is also -possible that the growth of Eozoon or the deposition of the serpentine -and pyroxene in which its remains have been preserved, or both, may -have been connected with certain oceanic depths and conditions, and -that we have as yet revealed to us the life of only certain stations in -the Laurentian seas. Whatever conjectures we may form on these more -problematic points, the observations above detailed appear to establish -the following conclusions:-- - -First, that in the Laurentian period, as in subsequent geological -epochs, the Rhizopods were important agents in the accumulation of -beds of limestone; and secondly, that in this early period these low -forms of animal life attained to a development, in point of magnitude -and complexity, unexampled, in so far as yet known, in the succeeding -ages of the earth's history. This early culmination of the Rhizopods is -in accordance with one of the great laws of the succession of living -beings, ascertained from the study of the introduction and progress of -other groups; and, should it prove that these great Protozoans were -really the dominant type of animals in the Laurentian period, this fact -might be regarded as an indication that in these ancient rocks we may -actually have the records of the first appearance of animal life on our -planet. - -With reference to the first of the above heads, I have now to state -that it seems quite certain that the upper and younger portions of -the masses of Eozoon often passed into the acervuline form, and the -period in which this change took place seems to have depended on -circumstances. In some specimens there are only a few regular layers, -and then a heap of irregular cells. In other cases a hundred or more -regular layers were formed; but even in this case little groups of -irregular cells occurred at certain points near the surface. I have -also found some masses clearly not fragmental which consist altogether -of acervuline cells. A specimen of this kind is represented in Fig. 52. -It is oval in outline, enclosed in a nodule of serpentine, about three -inches in length, wholly made up of rounded or cylindrical cells, the -walls of which have a beautiful tubular structure, but there is little -or no supplemental skeleton. Whether this is a portion accidentally -broken off from the top of a mass of Eozoon, or a peculiar varietal -form, or a distinct species, it would be difficult to determine. In -the meantime I have described it as a variety, "_acervulina_" of the -species Eozoon Canadense. It admits of comparison with a fragment -figured by Dr. Carpenter, which he compares with the chamberlets and -tubes of _Nummulites lævigata_ of the Eocene.[39] Another variety -also, from Petite Nation, shows extremely thin laminæ, closely placed -together and very massive, and with little supplemental skeleton. This -may be allied to the last, and may be named variety "_minor_."[40] - -[Footnote 39: _Proceedings of Geological Society_, 1875.] - -[Footnote 40: _Annals and Magazine of Natural History_, Sen 4, vol. -xiii. p. 457.] - -All this, however, has nothing to do with the layers of fragments of -Eozoon which are scattered through the Laurentian limestones. In these -the fossil is sometimes preserved in the ordinary manner, with its -cavities filled with serpentine, and the thicker parts of the skeleton -having their canals filled with this substance. In this case the -chambers may have been occupied with serpentine before it was broken -up. At St. Pierre there are distinct layers of this kind, from half an -inch to several inches in thickness, regularly interstratified with -the ordinary limestone. In other layers no serpentine occurs, but the -interstices of the fragments are filled with crystalline dolomite or -magnesian limestone, which has also penetrated the canals; and there -are indications, though less manifest, that some at least of the layers -of pure limestone are composed of fragmental Eozoon. - -[Illustration: Fig. 52.--_Acervuline Variety of Eozoon, Côte St. -Pierre._ - -(_a_) General form, half natural size. (_b_) Portion of cellular -interior, magnified, showing the course of the tubuli.] - -[Illustration: Fig. 53.--_Archæospherinæ from Côte St. Pierre._ - -(_a_) Specimens dissolved out by acid, the lower one showing interior -septa. (_b_) Specimens seen in section.] - -In the Laurentian limestone of Wentworth, belonging apparently to the -same band with that of St. Pierre, there are many small rounded pieces -of limestone, evidently the debris of some older rock, broken up and -rounded by attrition. In some of these fragments the structure of -Eozoon may be plainly perceived. This shows that still older limestones -composed of Eozoon were at that time undergoing waste, and carries our -view of the existence of this fossil back to the very beginning of the -Grenville series of the Laurentian. - -With respect to organic fragments not showing the structure of Eozoon, -I have not as yet been able to refer these to any definite origin. Some -of them may be simply thick portions of the shell of Eozoon with their -pores filled with calcite, so as to present a homogeneous appearance. -Others have much the appearance of fragments of such Primordial forms -as _Archæocyathus_, now usually regarded as corals or sponges; but -after much careful search, I have thus far been unable to say more than -I could say in 1865. - -It is different, however, with the round cells infiltrated with -serpentine and with the silicious grains included in the loganite. -Fig. 53 shows such bodies found mixed with fragmental Eozoon and in -separate thin layers at Côte St. Pierre. In Fig. 51, I have shown -some of the singular grains found in the loganite occupying the -chambers of Eozoon from Burgess, and in Fig. 54 some remarkable forms -of this kind found in the limestones of Long Lake and Wentworth. All -these, I think, are essentially of the same nature, namely, chambers -originally invested with a tubulated wall like Eozoon, and aggregated -in groups, sometimes in a linear manner, sometimes spirally, like those -Globigerinæ which constitute the mass of modern deep-sea dredgings and -also of the chalk. - -[Illustration: Fig. 54.--_Archæospherinæ from Long Lake Limestone._] - -(Magnified.) - -(_a_) Single cell, showing tubulated wall. (_b, c_) Portions of same -more highly magnified, (_d_) Casts decalcified, and showing casts of -tubules. - -These bodies occur dispersed in the limestone, arranged in thin layers -parallel to the bedding or sometimes in the large chamber-cavities of -Eozoon. They are so variable in size and form that it is not unlikely -they may be of different origins. The most probable of these may be -thus stated. First, they may in some cases be the looser superficial -parts of the surface of Eozoon broken up into little groups of cells. -Secondly, they may be few-celled germs or buds given off from Eozoon. -This would correspond with what Carpenter, and more recently Brady and -Lester, have observed in the case of some of the larger of the modern -Foraminifera. Thirdly, they may be smaller Foraminifera, structurally -allied to Eozoon, but in habit of growth resembling those little -globe-shaped forms which, as already stated, abound in chalk and in the -modern ocean. The latter view I should regard as highly probable in the -case of many of them; and I have proposed for them, in consequence, and -as a convenient name, _Archæospherinæ_ or ancient spherical animals. -Carbonaceous matter is rare in the true Eozoon limestones, and, as -already stated, I would refer the Laurentian graphite or plumbago -mainly to plants. - -Dr. Gümbel, the Director of the Geological Survey of Bavaria, is one of -the most active and widely informed of European geologists, combining -European knowledge with an extensive acquaintance with the larger and -in some respects more typical areas of the older rocks in America, and -stratigraphical geology with enthusiastic interest in the microscopic -structures of fossils. He at once, and in a most able manner, took up -the question of the application of the discoveries in Canada to the -rocks of Bavaria. The spirit in which he did so may be inferred from -the following extract:-- - -"The discovery of organic remains in the crystalline limestones of the -ancient gneiss of Canada, for which we are indebted to the researches -of Sir William Logan and his colleagues, and to the careful microscopic -investigations of Drs. Dawson and Carpenter, must be regarded as -opening a new era in geological science. - -"This discovery overturns at once the notions hitherto commonly -entertained with regard to the origin of the stratified primary -limestones, and their accompanying gneissic and quartzose strata, -included under the general name of primitive crystalline schists. It -shows us that these crystalline stratified rocks, of the so-called -primary system, are only a backward prolongation of the chain of -fossiliferous strata; the elements of which were deposited as oceanic -sediment, like the clay-slates, limestones, and sandstones of the -Palæozoic formations, and under similar conditions, though at a time -far more remote, and more favourable to the generation of crystalline -mineral compounds. - -"In this discovery of organic remains in the primary rocks, we hail -with joy the dawn of a new epoch in the critical history of these -earlier formations. Already in its light, the primeval geological time -is seen to be everywhere animated, and peopled with new animal forms -of whose very existence we had previously no suspicion. Life, which -had hitherto been supposed to have first appeared in the Primordial -division of the Silurian period, is now seen to be immeasurably -lengthened beyond its former limit, and to embrace in its domain the -most ancient known portions of the earth's crust. It would almost -seem as if organic life had been awakened simultaneously with the -solidification of the earth's crust." - -Gümbel has described from limestones of Laurentian age in various parts -of Europe forms referable to Eozoon or to Archæospherinæ, and I have -found fragmental Eozoon in specimens collected by Favre in the supposed -Archæan nucleus of the Alps. - -Gümbel also found in the Finnish and Bavarian limestones knotted -chambers, like those of Wentworth above mentioned (Fig. 55), which he -regards as belonging to some other organism than Eozoon; and flocculi -having tubes, pores, and reticulations which would seem to point to the -presence of structures akin to sponges or possibly remains of seaweeds. -These observations Gümbel has extended into other localities in Bavaria -and Bohemia, and also in Silesia and Sweden, establishing the existence -of Eozoon fossils in all the Laurentian limestones of the middle and -north of Europe. - -[Illustration: Fig. 55.--_Archæospherinæ from Pargas in Finland._ -(After Gümbel.) - -(Magnified.)] - -Gümbel has further found in beds overlying the older Eozoic series, -and probably of the same age with the Canadian Huronian, a different -species of Eozoon, with smaller and more contracted chambers, and -still finer and more crowded canals. This, which is to be regarded as -a distinct species, or at least a well-marked varietal form, he has -named _Eozoon Bavaricum_ (Fig. 56). Thus this early introduction of -life is not peculiar to that old continent which we sometimes call the -New World, but applies to Europe as well, and Europe has furnished a -successor to Eozoon in the later Eozoic or Huronian period. - -[Illustration: Fig. 56.--_Section of Eozoon Bavaricum, with Serpentine, -from the Crystalline Limestone of the Hercynian primitive Clay-slate -Formation at Hohenberg; 25 diameters (probably Huronian)._ - -(_a_) Sparry carbonate of lime, (_b_) Cellular carbonate of lime, (_c_) -System of tubuli. (_d_) Serpentine replacing the coarser ordinary -variety, (_e_) Serpentine and hornblende replacing the finer variety, -in the very much contorted portions.] - -In rocks of this age in America, after long search and much slicing of -limestones, I have hitherto failed to find any decided foraminiferal -remains other than the Tudor and Madoc specimens, which may be of this -age. They are laminated forms resembling Eozoon, but I have reason to -believe that their minute structure more closely resembles that of -Cryptozoon, though it is somewhat obscure. If these are really Huronian -and not Laurentian, the Eozoon from this horizon does not sensibly -differ from that of the Lower Laurentian. - -We are indebted to Mr. Matthew, of St. John, New Brunswick, who has so -greatly distinguished himself by his discoveries in the Cambrian of -that region, for some remarkable additions to the contemporaries of -Eozoon. One of these is a laminated body, like Eozoon in its general -appearance, but growing in crowded masses which by mutual pressure -become columnar (Fig. 57). In the best preserved specimens each layer -seems to consist of a thin lamina separated from its neighbours by -a finely granular mass, traversed by innumerable irregular tubes. -This recalls the structure of Cryptozoon of Hall, which, as we have -seen, is found in pre-Cambrian rocks in Colorado, and abounds in the -Upper Cambrian in New York, in Minnesota, and in different parts of -Canada, but Archæozoon differs in its form and habit of growth. If -the Stromatoporæ of the Ordovician and Silurian are hydroids, this -may also be the case with Cryptozoon; but so far as its own structure -is concerned, it approaches most nearly to the fossils known as -Loftusia in the Carboniferous and later formations, and these are -generally regarded as Foraminiferal. We may thus have another giant -Foraminiferal organism which contributed to the building up of rocks in -the Laurentian seas. - -[Illustration: Fig. 57.--_Archæozoon Acadiense_, Matthew. _Diagrammatic -transverse and longitudinal sections of a small specimen._ - -Specimen in Peter Redpath Museum.] - -_Pre-Palæozoic Rocks of Southern New Brunswick, as tabulated by -Matthew:--"_ - - +--+--+------------------------------------------------------------+ - | | | Thickness | - | | | Feet. | - | | | Coastal series (or system), 1872.-- | - | | | Grits, hydromicaschists, agillities, etc. | - | | | resembling the Pebidian rocks of Dr. H. | - | | | Hicks 10,000 | - | | | | - | |E | Coldbrook Series (or System), 1865.-- | - | |O | Diorites, felsites, petrosilex, etc.; | - | |Z | resembling the Arvonian rocks of Dr. | - | |O | Hicks. Thickness more than 15,000 | - | |I | | - | |C | Upper series (or system) of Laurentian, 1872. | - |A | | Upper division.--Argillites, | - |R | | limestones, graphitic shales. Fossils. In | - |C | | upper part of the upper limestones of the | - |H | | South basin, fragmental _Eozoon_, observed | - |Æ | | by Sir J. W. Dawson in specimens sent him. In | - |A | | middle of upper limestones in Middle basin, | - |N | | spicules of sponges. In graphitic shale | - | | | of South basin, spicules of _Halichondrites | - | | | graphitiferus_. In lowest limestone of | - | | | the Middle basin, the reef of columnar | - | | | fossils described as Archæozoon 740 | - | | | Middle division.--Quartzites, | - | | | silicious schists, Fossils _Cyathospongia (?) | - | | | eozoica_ near the top of this division 450 | - | | | Lower division.--Limestones and | - | |__| gneisses. No Fossils known 260[41]| - | | | Lower series of Laurentian.-- | - | | | Gneisses, Micaschists, etc ? | - +--+--+------------------------------------------------------------+ - -[Footnote 41: The above thicknesses are on the authority of Dr. L. -W. Bailey. _Report Progress Geological Survey Canada_, 1879, pp. 10, -D. D., and 21, D. D. Dr. R. W. Ells in the same Report, p. 6, D., -describes these rocks, sixty miles east of St. John, as one system, -with a thickness of 14,000 feet.] - -[Illustration: Fig. 57A.--_Archæozoon Acadiense_, Matthew. - -_Horizontal and vertical sections of a group of specimens, reduced._ - -(From Photographs.)] - -This discovery is also of importance as connecting Eozoon through -Cryptozoon with large organisms, probably Protozoa, extending upward to -the top of the Cambrian, and thus forming a link of connection between -the life of the Eozoic and that of the Palæozoic period. Matthew has -also described forms which he regards as spicules of sponges from -the Laurentian of New Brunswick.[42] One of these seems to present -cruciform needles forming square areas, like the Protospongia of -Salter, from the Cambrian. The other has simple elongate needle-like -spicules arranged in bundles. Matthew summarizes the rocks containing -these fossils as in the table on p, 216, in descending order, the -highest bed being below the Etcheminian.[43] The first and second -groups, it will be observed, are equivalent to the Huronian; the third -corresponds to the Grenvillian, and the fourth to the Lower Laurentian. - -[Footnote 42: Fuller descriptions of these rocks may be found in _Rep. -Prog. Geol. Surv. of Canada_, 1872, pp. 30, 34, etc.] - -[Footnote 43: _Bulletin Nat. Hist. Society of New Brunswick_, 1890 -where further details are given as to the fossils.] - - - - - _DIFFICULTIES AND OBJECTIONS_ - - - - - IX - - _DIFFICULTIES AND OBJECTIONS_ - - -The active objectors to the animal nature of Eozoon have been few, -though some of them have returned to the attack with a pertinacity and -determination which would lead one to believe that they think the most -sacred interests of science to be dependent on the annihilation of this -proto-foraminifer. I do not propose here to treat of the objections in -detail. I have presented the case of Eozoon on its own merits, and on -these it must stand. I may merely state that the objectors strive to -account for the existence of Eozoon by purely mineral deposition, and -that the complicated changes which they require to suppose are perhaps -the strongest indirect evidence for the necessity of regarding the -structures as organic. The reader who desires to appreciate this may -consult my memoir of 1888.[44] - -[Footnote 44: Also Rowney and King's papers in _Journal Geological -Society_, August, 1866; and _Proceedings Irish Academy_, 1870 and -1871.] - -I confess that I feel disposed to treat very tenderly the position -of objectors. The facts I have stated make large demands on the -faith of the greater part even of naturalists. Very few geologists -or naturalists have much knowledge of the structure of foraminiferal -shells, or would be able under the microscope to recognise them with -certainty. Nor have they any distinct ideas of the appearances of such -structures under different kinds of preservation and mineralization. -Further, they have long been accustomed to regard the so-called Azoic -or Archæan rocks as not only destitute of organic remains, but as -being in such a state of metamorphism that these could not have been -preserved had they existed. Few, therefore, are able intelligently -to decide for themselves, and so they are called on to trust to the -investigations of others, and on their testimony to modify in a marked -degree their previous beliefs as to the duration of life on our planet. -In these circumstances it is rather wonderful that the researches made -with reference to Eozoon have met with so general acceptance, and -that the resurrection of this ancient inhabitant of the earth has not -aroused more of the sceptical tendency of our age. - -It must not be lost sight of, however, that in such cases there may -exist a large amount of undeveloped and even unconscious scepticism, -which shows itself not in active opposition, but merely in quietly -ignoring this great discovery, or regarding it with doubt, as an -uncertain or unestablished point in science. Such scepticism is -especially to be expected on the part of the many enthusiastic students -of petrography who are accustomed to regard rocks merely as mineral -aggregates, and even to have their slices prepared in a manner which -scarcely permits organic remains of present to be distinguished. -Such students should consider that the discovery of Eozoon brings -the rocks of the Laurentian system into more full harmony with the -other geological formations. It explains the origin of the Laurentian -limestones in consistency with that of similar rocks in the later -periods, and in like manner it helps us to account for the graphite -and sulphides and iron ores of these old rocks. It shows us that no -time was lost in the introduction of life on the earth. Otherwise there -would have been a vast lapse of time in which, while the conditions -suitable to life were probably present, no living thing existed to -take advantage of these conditions. Further, it gives a more simple -beginning of life than that afforded by the more complex fauna of the -Cambrian age; and this is more in accordance with what we know of the -slow and gradual introduction of new forms of living things during the -vast periods of Palæozoic time. In connection with this, it opens a -new and promising field of observation in the older rocks; and if this -should prove fertile, its exploration may afford a vast harvest of new -forms to the geologists of the present and coming time. This result -will be in entire accordance with what has taken place before in the -history of geological discovery. I can myself remember a time when the -old and semi-metamorphic sediments constituting the great Cambrian -system were massed together in geological classifications as primitive -or primary rocks, destitute or nearly destitute of organic remains. -The brilliant discoveries of Sedgwick, Murchison, Barrande, and a -host of others, have peopled these once barren regions; and they now -stretch before our wondering gaze in the long vistas of early Palæozoic -life. So we now look out from the Cambrian shore upon the ocean of the -Etcheminian, the Huronian, and the Laurentian--all to us yet almost -tenantless, except for the few organisms which, like stray shells cast -upon the beach, or a far-off land dimly seen in the distance, incite -to further researches, and to the exploration of the unknown treasures -that still lie undiscovered. It would be a suitable culmination of -the geological work of the last half-century, and one within reach at -least of our immediate successors, to fill up this great blank, and to -trace back the Primordial life to the stage of Eozoon, and perhaps even -beyond this, to predecessors which may have existed at the beginning -of the Laurentian, when the earliest sediments of that great formation -were laid down. Vast unexplored areas of Laurentian and Huronian rocks -exist in the Old World and the New. The most ample facilities for -microscopic examination of rocks may now be obtained; and I could wish -that one result of the publication of these pages may be to direct the -attention of some of the younger and more active geologists to these -fields of investigation. It is to be observed also that such regions -are among the richest in useful minerals, and there is no reason why -search for these fossils should not be connected with other and more -practically useful researches. On this subject it will not be out of -place to quote the remarks which I made in one of my earlier papers on -the Laurentian fossils:-- - -"This subject opens up several interesting fields of chemical, -biological, and geological inquiry. One of these relates to the -conclusions stated by Dr. Hunt as to the probable existence of a -large amount of carbonic acid in the Laurentian atmosphere, and of -much carbonate of lime in the seas of that period, and the possible -relation of this to the abundance of certain low forms of plants and -animals. Another is the comparison already instituted by Professor -Huxley and Dr. Carpenter, between the conditions of the Laurentian and -those of the deeper parts of the modern ocean. Another is the possible -occurrence of other forms of animal life than Protozoa, which I have -stated in my paper of 1864, after extensive microscopic study of the -Laurentian limestones, to be indicated by the occurrence of calcareous -fragments, differing in structure from Eozoon, but at present of -unknown nature. Another is the effort to bridge over, by further -discoveries [similar to those of Cryptozoon and Archæozoon], the gap -now existing between the life of the Lower Laurentian and that of the -Cambrian period. It is scarcely too much to say that these inquiries -open up a new world of thought and investigation, and hold out the -hope of bringing us into the presence of the actual origin of organic -life on our planet, though this may perhaps be found to have been -pre-Laurentian. I would here take the opportunity of repeating that, -in proposing the name Eozoon for the first fossil of the Laurentian, -and in suggesting for the period the name 'Eozoic,' I have by no means -desired to exclude the possibility of forms of life which may have been -precursors of what is now to us the dawn of organic existence. Should -remains of still older organisms be found in those rocks now known to -us only by pebbles in the Laurentian, these names will at least serve -to mark an important stage in geological investigation." - -But what if the result of such investigations should be to produce more -sceptics, or to bring to light mineral structures so resembling Eozoon -as to throw doubt upon the whole of the results detailed in these -chapters? I can fancy that this might be the first consequence, more -especially if the investigations were those of persons more conversant -with rocks and minerals than with fossils; but I see no reason to -fear the ultimate results. In any case, no doubt, the value of the -researches hitherto made may be diminished. It is always the fate of -discoverers in Natural Science, either to be followed by opponents who -temporarily or permanently impugn or destroy the value of their new -facts, or by other investigators who push on the knowledge of facts and -principles so far beyond their standpoint that the original discoveries -are cast into the shade. This is a fatality incident to the progress of -scientific work, from which no man can be free; and in so far as such -matters are concerned, we must all be content to share the fate of the -old fossils whose history we investigate, and, having served our day -and generation, to give place to others. If any part of our work should -stand the fire of discussion, let us be thankful. One thing at least -is certain, that such careful surveys as those in the Laurentian rocks -of Canada which led to the discovery of Eozoon, and such microscopic -examinations as those by which it has been worked up and presented to -the public, cannot fail to yield good results of one kind or another. -Already the attention excited by the controversies about Eozoon, -by attracting investigators to the study of various microscopic and -imitative forms in rocks, has promoted the advancement of knowledge, -and must do so still more. For my own part, though I am not content to -base all my reputation on such work as I have done with respect to this -old fossil--which, indeed, was merely an interlude into which I was led -by the urgency of my friend Logan--I am willing at least to take the -responsibility of the results I have announced, whatever conclusions -may be finally reached; and in the consciousness of an honest effort -to extend the knowledge of nature, to look forward to a better fame -than any that could result from the most successful and permanent -vindication of every detail of our scientific discoveries, even if they -could be pushed to a point which no subsequent investigation in the -same difficult line of research would be able to overpass. - -Contenting myself with these general remarks, I shall close this -chapter with a short summary of the reasons which may be adduced -in support of the animal nature of Eozoon, prefaced by an ideal -restoration of it in the supposition that it was a rhizopod (Fig. 58). - -[Illustration: Fig. 58.--_Restoration of Eozoon as a generalized -Foraminiferal Organism (enlarged)._ - -Showing endosarc, exosarc, and pseudopods, and the calcareous skeleton -with its canals.] - -In doing so, I shall merely sum up the evidence as it has been -presented by Sir W. E. Logan, Dr. Carpenter, Dr. Hunt, and the author, -in a short and intelligible form; and I shall do so under a few brief -heads, with some explanatory remarks:-- - -1. The Upper Laurentian of Canada, a rock formation whose distribution, -age, and structure have been carefully worked out in several extensive -districts by the Canadian Survey, is found to contain thick and widely -distributed beds of limestone, related to the other beds in the same -way in which limestones occur in the sediments of other geological -formations. There also occur in the same formation, graphite, iron -ores, and metallic sulphides, in such relations as to suggest the idea -that the limestones as well as these other minerals are of organic -origin. - -2. In the limestones are found laminated bodies of definite form and -structure, composed of calcite alternating with serpentine and other -minerals. The forms of these bodies suggested a resemblance to the -Silurian Stromatoporæ, and the different mineral substances associated -with the calcite in the production of similar forms showed that these -were not accidental or concretionary. - -3. On microscopic examination, it proved that the calcareous laminæ -of these forms were similar in structure to the shells of modern -and fossil Foraminifera, more especially those of the Rotaline and -Nummuline types, and that the finer structures, though usually filled -with serpentine and other hydrous silicates, were sometimes occupied -with calcite, pyroxene, or dolomite, showing that they must when recent -have been empty canals and tubes. - -4. The mode of filling thus suggested for the chambers and tubes of -Eozoon is precisely that which takes place in modern Foraminifera -filled with glauconite, and in Palæozoic crinoids and corals filled -with other hydrous silicates, all more or less chemically allied to -serpentine. - -5. The type of growth and structure predicated of Eozoon from the -observed appearances, in its great size, its laminated and acervuline -forms, and in its canal system and tubulation, are not only in -conformity with those of other Foraminifera, but such as might be -expected in a very ancient form of that group. - -6. Indications exist of other organic bodies in the limestones -containing Eozoon, and also of the Eozoon being preserved not only in -reefs but in drifted fragmental beds as in the case of modern corals. - -7. Similar organic structures have been found in the Laurentian -limestones of Massachusetts, New York, Brazil,[45] and also in those -of various parts of Europe, and Dr. Gümbel has found an additional -species in rocks succeeding the Laurentian. - -[Footnote 45: Fragmental; specimens from J. A. Derby, Esq.] - -8. The manner in which the structures of Eozoon are effected by the -faulting, development of crystals, mineral veins, and other effects of -disturbance and metamorphism in the containing rocks, is precisely that -which might be expected on the supposition that it is of organic origin. - -9. The exertions of several active and able opponents have failed to -show how, otherwise than by organic agency, such structures as those -of Eozoon can be formed, except on the supposition of pseudo-morphism -and replacement, which must be regarded as chemically extravagant, -and which would equally impugn the validity of all fossils determined -by microscopic structure. In like manner all comparisons of these -structures with dendritic and other imitative forms have signally -failed, in the opinion of those best qualified to judge. - -Another and perhaps simpler way of putting the case is the -following:--Only four general modes of accounting for the existence -of Eozoon have been proposed. The first is that of Professors King -and Rowney, who regard the chambers and canals filled with serpentine -as arising from the erosion or partial dissolving away of serpentine -and its replacement by calcite. The objections to this are conclusive. -It does not explain the fine tubulation, which has to be separately -accounted for by confounding it, contrary to the observed facts, -with the veins of fibrous serpentine which actually pass through -cracks in the fossil. Such replacement is in the highest degree -unlikely on chemical grounds, and there is no evidence of it in the -numerous serpentine grains, nodules, and bands in the Laurentian -limestones. On the other hand, the opposite replacement, that of -limestone by serpentine, seems to have occurred. The mechanical -difficulties in accounting for the delicate canals on this theory are -also insurmountable. Finally, it does not account for the specimens -preserved in pyroxene and other silicates, and in dolomite and calcite. -A second mode of accounting for the facts is that the Eozoon forms are -merely peculiar concretions. But this fails to account for their great -difference from the other serpentine concretions in the same beds, and -for their regularity of plan and the delicacy of their structure, and -also for minerals of different kinds entering into their composition, -and still presenting precisely the same forms and structures. The third -is that first suggested, I think, by Jullien, and later by Gregory and -Lavis, that the forms are merely banded alternations of calcite with -silicious minerals similar to those observed at the junction of igneous -rocks and limestones. To this it may be replied that there is really -only an apparent resemblance, which, on careful examination, proves -to be illusory; that it does not account for the canals and tubuli, -and that studies of such banded rocks from several regions have been -made by competent observers, who have distinguished these from the -Laurentian Eozoon. The only remaining theory is that of the filling -of cavities by infiltration with serpentine. This accords with the -fact that such infiltration by minerals akin to serpentine exists in -fossils in later rocks. It also accords with the known aqueous origin -of the serpentine nodules and bands, the veins of fibrous serpentine, -and the other minerals found filling the cavities of Eozoon. Even the -pyroxene has been shown by Hunt to exist in the Laurentian in veins -of aqueous origin. The only difficulty existing on this view is how -a calcite skeleton with such chambers, canals, and tubuli could be -formed; and this is solved by the discovery that all these facts -correspond precisely with those to be found in the shells of modern -oceanic Foraminifera. The existence, then, of Eozoon, its structure, -and its relations to the containing rocks and minerals being admitted, -no rational explanation of its origin seems at present possible other -than that advocated in the preceding pages. - -If the reader will now turn to the figures in the illustration on the -opposite page (Fig. 59), he will find a selection of examples bearing -on the above arguments and objections. Fig. 1 represents a portion of a -very thin slice of a specimen traversed by veins of fibrous serpentine -or chrysotile, and having the calcite of the walls more broken by -cleavage planes than usual. The portion selected shows a part of one -of the chambers filled with serpentine, which presents the usual -curdled aspect almost impossible to represent in a drawing (_s_). It -is traversed by a branching vein of chrysotile (_s′_), which, where -cut precisely parallel to its fibres, shows clear fine cross lines, -indicating the sides of its constituent prisms, and where the plane of -section has passed obliquely to its fibres, has a curiously stippled or -frowsy appearance. - -[Illustration: Fig. 59.--_Figures of various Structures and States of -Preservation._ - - Fig. 1.--Portion of two laminæ and intervening serpentine, with - chrysotile vein. (_a_) Proper wall tubulated. (_b_) Intermediate - skeleton, with large canals. (_c_) Openings of small chamberlets - filled with serpentine. (_s_) Serpentine filling chamber. (_s¹_) - Vein of chrysotile, showing its difference from the proper wall. - - Fig. 2.--Junction of a canal and the proper wall. Lettering as in - Fig. 1. - - Fig. 3.--Proper wall shifted by a fault, and more recent chrysotile - vein not faulted. Lettering as in Fig. 1. - - Fig. 4.--Large and small canals filled with dolomite. - - Fig. 5.--Abnormally thick portion of intermediate skeleton, with - large tubes and small canals filled with dolomite. -] - -On either side of the serpentine band is the nummuline or proper wall, -showing under a low power a milky appearance, which, with a higher -power, becomes resolved into a tissue of the most beautiful parallel -threads, representing the filling of its tubuli. Nothing can be more -distinct than the appearances presented by this wall and a chrysotile -vein, under every variety of magnifying power and illumination; and all -who have had an opportunity of examining my specimens have expressed -astonishment that appearances so dissimilar should have been confounded -with each other. On the lower side two indentations are seen in the -proper wall (_c_). These are connected with the openings into small -subordinate chamberlets, one of which is in part included in the -thickness of the slice. At the upper and lower parts of the figure -are seen portions of the intermediate skeleton traversed by canals, -which in the lower part are very large, though from the analogy of -other specimens it is probable that they have in their interstices, -and at their branching extremities, minute canaliculi not visible in -this slice. Fig. 2, from the same specimen, shows the termination of -one of the canals against the proper wall, its end expanding into a -wide disc of sarcode on the surface of the wall, as may be seen in -similar structures in modern Foraminifera. In this specimen the canals -are beautifully smooth and cylindrical, but they sometimes present a -knotted or jointed appearance, especially in specimens decalcified -by acids, in which perhaps some erosion has taken place. They are -also occasionally fringed with minute crystals, especially in those -specimens in which the calcite has been partially replaced with other -minerals. Fig. 3 shows an example of faulting of the proper wall, an -appearance not infrequently observed; and it also shows a vein of -chrysotile crossing the line of fault, and not itself affected by it--a -clear evidence of its posterior origin. Figs. 4 and 5 are examples of -specimens having the canals filled with dolomite, and showing extremely -fine canals in the interstices of the others: an appearance observed -only in the thicker parts of the skeleton, and when these are very well -preserved. These dolomitized portions require some precautions for -their observation, either in slices or decalcified specimens, but when -properly managed they show the structures in very great perfection. The -specimen in Fig. 5 is from an abnormally thick portion of intermediate -skeleton, having unusually thick canals, and referred to in a previous -chapter. Such additional peculiarities and specialties might be -multiplied to any extent from the numerous prepared specimens now in -our collections. - -One object which I have in view in thus minutely directing attention -to these illustrations, is to show the nature of the misapprehensions -which may occur in examining specimens of this kind, and at the same -time the certainty which may be attained when proper precautions are -taken. I may add that such structures as those referred to are best -seen in extremely thin slices, and that the observer must not expect -that every specimen will exhibit them equally well. It is only by -preparing and examining many specimens that the best results can be -obtained. It often happens that one specimen is required to show well -one part of the structures, and a different one to show another; and -previous to actual trial, it is not easy to say which portion of the -structures any particular fragment will show most clearly. This renders -it somewhat difficult to supply one's friends with specimens. Really -good slices can be prepared only from the best material and by skilled -manipulators; imperfect slices may only mislead; and rough specimens -may not be properly prepared by persons unaccustomed to the work, or -if so prepared, may not turn out satisfactory, or may not be skilfully -examined. One slice heated in the grinding may show nothing but -cleavage in the calcite layers, while an adjoining one more carefully -prepared may show beautiful canals. These difficulties, however, Eozoon -shares with other specimens in micro-geology, and I have experienced -similar disappointments in the case of fossil wood. - -In conclusion of this part of the subject, and referring to the notes -appended to this work for some further details, I would express the -hope that those who have hitherto opposed the interpretation of Eozoon -as organic, and to whose ability and honesty of purpose I willingly -bear testimony, will find themselves enabled to acknowledge at least -the reasonable probability of that interpretation of these remarkable -forms and structures. - - - - - _THE ORIGIN OF LIFE_ - - - - - X - - _THE ORIGIN OF LIFE_ - - -The thoughts suggested to the philosophical naturalist by the -contemplation of the dawn of life on our planet are necessarily many -and exciting, and the subject has in it the materials for enabling the -general reader better to judge of some of the theories of the origin of -life agitated in our time. Let us then put Eozoon into the witness-box, -and try to elicit its testimony as to the beginnings of life; supposing -for the moment that it is really an animal, and not a mere pretender; -though even in that case, it might serve to represent the first animal, -whatever it may have been. - -Looking down from the elevation of our physiological and mental -superiority, it is difficult to realize the exact conditions in which -life exists in creatures so simple as the Protozoa. There may perhaps -be higher intelligences that find it equally difficult to realize how -life and reason can manifest themselves in such poor houses of clay -as those we inhabit. But placing ourselves near to these creatures, -and entering as it were into sympathy with them, we can understand -something of their powers and feelings. In the first place, it is -plain that they can vigorously, if roughly, exercise those mechanical, -chemical, and vegetative powers of life which are characteristic of -the animal. They can seize, swallow, digest, and assimilate food; and, -employing its albuminous parts in nourishing their tissues, can burn -away the rest in processes akin to our respiration, or reject it from -their system. Like us, they can subsist only on food which the plant -has previously produced; for in this world, from the beginning of time, -the plant has been the only organism which could use the solar light -and heat as forces to enable it to turn the dead elements of matter -into living, growing tissues, and into organic compounds capable of -nourishing the animal. Like us, the Protozoa expend the food which -they have assimilated in the production of animal force, and in doing -so cause it to be oxidized, or burnt away, and resolved again into -dead matter. It is true that we have much more complicated apparatus -for performing these functions, but it does not follow that this gives -us much real superiority, except relatively to the more difficult -conditions of our existence. The gourmand who enjoys his dinner may -have no more pleasure in the act than the Amœba which swallows a -Diatom; and for all that the man knows of the subsequent processes to -which the food is subjected, his interior might be a mass of jelly, -with extemporised vacuoles, like that of his humble fellow-animal. The -workman or the athlete has bones and muscles of vastly complicated -structure, but to him the muscular act is as simple and unconscious a -process as the sending out of a pseudopod to a Protozoon. The clay is -after all the same, and there may be as much credit to the artist in -making a simple organism with varied powers, as a more complex frame -for doing nicer work. It is a weakness of humanity to plume itself on -advantages not of its own making, and to treat its superior gifts as -if they were the result of its own endeavours. The truculent traveller -who illustrated his boast of superiority over the Indian by comparing -his rifle with the bow and arrows of the savage, was well answered by -the question, "Can you make a rifle?" and when he had to answer, "No," -by the rejoinder, "Then I am at least better than you, for I can make -my bow and arrows." The Amœba or the Eozoon is probably no more than -we its own creator; but if it could produce itself out of vegetable -matter, or out of inorganic substances, it might claim in so far a -higher place in the scale of being than we; and as it is, it can assert -equal powers of digestion, assimilation, and motion, with much less of -bodily mechanism. - -In order that we may feel, a complicated apparatus of nerves and -brain-cells has to be constructed and set to work; but the Protozoon, -without any distinct brain, is all brain, and its sensation is simply -direct. Thus vision in these creatures is probably performed in a rough -way by any part of their transparent bodies, and taste and smell are -no doubt in the same case. Whether they have any perception of sound -as distinct from the mere vibrations ascertained by touch, we do not -know. Here also we are not far removed above the Protozoa, especially -those of us to whom touch, seeing, and hearing are mere feelings, -without thought or knowledge of the apparatus employed. We might so far -as well be Amœbas. As we rise higher we meet with more differences. -Yet it is evident that our gelatinous fellow-being can feel pain, -dread danger, desire possessions, enjoy pleasure, and in a simple, -unconscious way entertain many of the appetites and passions that -affect ourselves. The wonder is that with so little of organization it -can do so much. Yet, perhaps, life can manifest itself in a broader -and more intense way where there is little organization; and a highly -strung and complex organism is not so much a necessary condition of -a higher life as a mere means of better adapting it to its present -surroundings. Those philosophies which identify the thinking mind with -the material organism, must seem outrageous blunders to an Amœba on -the one hand, or to an angel on the other, could either be enabled to -understand them; which, however, is not very probable, as they are too -intimately bound up with the mere prejudices incident to the present -condition of our humanity. In any case, the Protozoa teach us how much -of animal function may be fulfilled by a very simple organism, and warn -us against the fallacy that creatures of this simple structure are -necessarily nearer to inorganic matter, and more easily developed from -it than beings of more complex mould. - -A similar lesson is taught by the complexity of their skeletons. We -speak in a crude, unscientific way of these animals accumulating -calcareous matter, and building up reefs of limestone. We must, -however, bear in mind that they are as dependent on their food for -the materials of their skeletons as we are, and that their crusts -grow in the interior of the sarcode just as our bones do within our -bodies. The provision even for nourishing the interior of the skeleton -by tubuli and canals is in principle similar to that involved in the -Haversian canals, cells, and canalicules of bone. The Protozoon of -course knows neither more nor less of this than the average Englishman. -It is altogether a matter of unconscious growth. The process in -the Protozoa strikes some minds, however, as the more wonderful of -the two. It is, says an eminent modern physiologist, a matter of -"profound significance" that this "particle of jelly [the sarcode -of a Foramlnifer] is capable of guiding physical forces in such a -manner as to give rise to these exquisite and almost mathematically -arranged structures." Respecting the structures themselves, there is -no exaggeration in this. No arch or dome framed by human skill is more -perfect in beauty or in the realization of mechanical ideas than the -tests of some Foraminifera, and none is so complete and wonderful in -its internal structure. The particle of jelly, however, is a figure of -speech. The body of the humblest Foramlnifer is much more than this. -It is an organism with divers parts, as we have already seen in a -previous chapter, and It is endowed with the mysterious forces of life -which in it guide the physical forces, just as they do in building -up phosphate of lime in our bones, or indeed just as the will of the -architect does in building a palace. The profound significance which -this has, reaches beyond the domain of the physical and vital, even to -the spiritual. It clings to all our conceptions of living things: quite -as much, for example, to the evolution of an animal, with all its parts -from a one-celled germ, or to the connection of brain-cells with the -manifestations of intelligence. Viewed in this way, we may share with -the author of the sentence I have quoted his feeling of veneration in -the presence of this great wonder of animal life, "burning, and not -consumed," nay, building up, and that in many and beautiful forms. We -may realize it most of all in the presence of the organism which was -perhaps the first to manifest on our planet these marvellous powers. -We must, however, here, also, beware of that credulity which makes too -many thinkers limit their conceptions altogether to physical force -in matters of this kind. The merely materialistic physiologist is -really in no better position than the savage who quails before the -thunderstorm, or rejoices in the solar warmth, and seeing no force or -power beyond, fancies himself in the immediate presence of his God. In -Eozoon we must discern not only a mass of jelly, but a being endowed -with that higher vital force which surpasses vegetable life and also -physical and chemical forces; and in this animal energy we must see an -emanation from a Will higher than our own, ruling vitality itself; and -this not merely to the end of constructing the skeleton of a Protozoon, -but of elaborating all the wonderful developments of life that were to -follow in succeeding ages, and with reference to which the production -and growth of this creature were initial steps. It is this mystery of -design which really constitutes the "profound significance" of the -foraminiferal skeleton. - -Another phenomenon of animality forced upon our notice by the Protozoa -is that of the conditions of life in animals not individual, as we -are, but aggregative and accumulative in indefinite masses. What, for -instance, the relations to each other of the Polyps, growing together -in a coral mass, of the separate parts of a Sponge, or the separate -cells of a Foraminifer, or of the sarcode mass of an indefinitely -spread out Cryptozoon. In the case of the Polyps, we may believe that -there is special sensation in the tentacles and oral opening of each -individual, and that each may experience hunger when in want, or -satisfaction when it is filled with food, and that injuries to one part -of the mass may indirectly affect other parts, but that the nutrition -of the whole mass may be as much unfelt by the individual Polyps as -the processes going on in our own bones are by us. So in the case of -a large Sponge or Foraminifer, there may be some special sensation in -individual cells, pseudopods, or segments, and the general sensation -may be very limited, while unconscious living powers pervade the whole. -In this matter of aggregation of animals we have thus various grades. -The Foraminifers and Sponges present us with the simplest of all, and -that which most resembles the aggregation of buds in the plant. The -Polyps and complex Bryozoons present a higher and more specialized -type; and though the bilateral symmetry which obtains in the higher -animals is of a different nature, it still at least reminds us of that -multiplication of similar parts which we see in the lower grades of -being. It is worthy of notice here that the lower animals which show -aggregative tendencies present but imperfect indications, or none -at all, of bilateral symmetry. Their bodies, like those of plants, -are for the most part built up around a central axis, or they show -tendencies to spiral modes of growth. - -It is this composite sort of life which is connected with the main -geological function of the Foraminifer. While active sensation, -appetite, and enjoyment pervade the pseudopods and external sarcode -of the mass, the hard skeleton common to the whole is growing within; -and in this way the calcareous matter is gradually removed from -the sea-water, and built up in solid reefs, or in piles of loose -foraminiferal shells. Thus it is the aggregative or common life, -alike in Foraminifers as in Corals, that tends most powerfully to the -accumulation of calcareous matter; and those creatures whose life is -of this complex character are best suited to be world-builders, since -the result of their growth is not merely a cemetery of their osseous -remains, but a huge communistic edifice, to which multitudes of lives -have contributed, and in which successive generations take up their -abode on the remains of their ancestors. This process, so potent in the -progress of the earth's geological history, began, as far as we know, -with Eozoon. - -Whether, then, in questioning our proto-foraminifer, we have reference -to the vital functions of its gelatinous sarcode, to the complexity and -beauty of its calcareous test, or to its capacity for effecting great -material results through the union of individuals, we perceive that we -have to do, not with a low condition of those powers which we designate -life, but with the manifestation of those powers through the means of a -simple organism; and this in a degree of perfection which we, from our -point of view, would have in the first instance supposed impossible. - -If we imagine a world altogether destitute of life, we still might -have geological formations in progress. Not only would volcanoes belch -forth their liquid lavas and their stones and ashes, but the waves and -currents of the ocean and the rains and streams on the land, with the -ceaseless decomposing action of the carbonic acid of the atmosphere, -would be piling up mud, sand, and pebbles in the sea. There might even -be some formation of limestone taking place where springs charged -with bicarbonate of lime were oozing out on the land or the bottom of -the waters. But in such a world all the carbon would be in the state -of carbonic acid, and all the limestone would either be diffused in -small quantities through various rocks or in limited local beds, or -in solution, perhaps as chloride of calcium, in the sea. Dr. Hunt has -given chemical grounds for supposing that the most ancient seas were -largely supplied with this very soluble salt, instead of the chloride -of sodium, or common salt, which now prevails in the sea-water. - -Where in such a world would life be introduced? on the land or in the -waters? All scientific probability would say in the latter. The ocean -is now vastly more populous than the land. The waters alone afford -the conditions necessary at once for the most minute and the grandest -organisms, at once for the simplest and for others of the most complex -character. Especially do they afford the best conditions for those -animals which subsist in complex communities, and which aggregate large -quantities of mineral matter in their skeletons. So true is this that -up to the present time all the species of Protozoa and of the animals -most nearly allied to them are aquatic. Even in the waters, however, -plant life, though possibly in very simple forms, must precede the -animal. - -Let humble plants, then, be introduced in the waters, and they would -at once begin to use the solar light for the purpose of decomposing -carbonic acid, and forming carbon compounds which had not before -existed, and which independently of vegetable life would never have -existed. At the same time lime and other mineral substances present in -the sea-water would be fixed in the tissues of these plants, either -in a minute state of division, as little grains or Coccoliths, or in -more solid masses like those of the Corallines and Nullipores. In this -way a beginning of limestone formation might be made, and quantities -of carbonaceous and bituminous matter, resulting from the decay of -marine plants, might accumulate in the sea-bottom. The plants have -collected stores of organic matter, and their minute germs, along -with microscopic species, are floating everywhere in the sea. Nay, -there may be abundant examples of those Amœba-like germs of aquatic -plants, simulating for a time the life of the animal, and then -returning into the circle of vegetable life. In these some might see -precursors of the Protozoa, though they are probably rather prophetic -analogues than blood relations. The plant has fulfilled its function -as far as the waters are concerned, and now arises the opportunity -for the animal. In what form shall it appear? Many of its higher -forms, those which depend upon animal food or on the more complex -plants for subsistence, would obviously be unsuitable. Further, the -sea-water is still too much saturated with saline matter to be fit -for the higher animals of the waters. Still further, there may be a -residue of internal heat forbidding coolness, and that solution of free -oxygen which is an essential condition of existence to most of the -modern animals.[46] Something must be found suitable for this saline, -imperfectly oxygenated, tepid sea. Something too is wanted that can aid -in introducing conditions more favourable to higher life in the future. -Our experience of the modern world shows us that all these conditions -can be better fulfilled by the Protozoa than by any other creatures. -They can live now equally in those great depths of ocean where the -conditions are most unfavourable to other forms of life, and in tepid -unhealthy pools overstocked with vegetable matter in a state of -putridity. They form a most suitable basis for higher forms of life. -They have remarkable powers of removing mineral matters from the waters -and of fixing them in solid forms. So in the fitness of things Eozoon -is just what we need, and after it has spread itself over the mud and -rock of the primeval seas, and built up extensive reefs therein, other -animals may be introduced capable of feeding on it, or of sheltering -themselves in its stony masses, and thus we have the appropriate dawn -of animal life. - -[Footnote 46: It has been assumed that any temperature over 120° -Fahrenheit would be incompatible with ordinary aquatic life. Still such -life is at least possible in some form up to 200°.] - -But what are we to say of the cause of this new series of facts, so -wonderfully superimposed upon the merely vegetable and mineral? Must -it remain to us as an act of creation, or was it derived from some -pre-existing matter in which it had been potentially present ? Science -fails to inform us, but conjectural "phylogeny" steps in and takes its -place. Haeckel, one of the prophets of this new philosophy, waves his -magic wand, and simple masses of sarcode spring from inorganic matter, -and form diffused sheets of sea-slime, from which are in time separated -distinct Amœboid and Foraminiferal forms. Experience, however, gives us -no facts whereon to build this supposition, and it remains neither more -nor less scientific or certain than that old fancy of the Egyptians, -which derived animals from the fertile mud of the Nile. - -If we fail to learn anything of the origin of Eozoon, and if its -life-processes are just as inscrutable as those of higher creatures, -we can at least inquire as to its history in geological time. In this -respect we find in the first place that the Protozoa have not had -a monopoly in their profession of accumulators of calcareous rock. -Originated by Eozoon in the old Laurentian time, this process has -been proceeding throughout the geological ages; and while Protozoa, -equally simple with the great prototype of the race, have been and -are continuing its function, and producing new limestones in every -geological period, and so adding to the volume of the successive -formations, new workers of higher grades have been introduced, capable -of enjoying higher forms of animal activity, and equally of labouring -at the great task of continent-building; of existing, too, in seas -less rich in mineral substances than those of the Eozoic time, and for -that very reason better suited to higher and more skilled artists. -It is to be observed in connection with this, that as the work of -the Foraminifers has thus been assumed by others, their size and -importance have diminished, and the grander forms of more recent times -have some of them been fain to build up their hard parts of cemented -sand instead of limestone. - -But we further find that, while the first though not the only organic -gatherers of limestone from the ocean waters, they have had to do, not -merely with the formation of calcareous sediments, but also with that -of silicious deposits. The greenish silicate called glauconite, or -green-sand, is found to be associated with much of the foraminiferal -slime now accumulating in the ocean, and also with the older deposits -of this kind now consolidated in chalks and similar rocks. This name -glauconite is, as Dr. Hunt has shown, employed to designate not only -the hydrous silicate of iron and potash, which perhaps has the best -right to it, but also compounds which contain in addition large -percentages of alumina, or magnesia, or both; and one glauconite from -the Tertiary limestones near Paris is said to be a true serpentine, -or hydrous silicate of magnesia.[47] Now the association of such -substances with Foraminifera is not purely accidental. Just as a -fragment of decaying wood, imbedded in sediment, has the power of -decomposing soluble silicates carried to it by water, and parting with -its carbon in the form of carbonic acid, in exchange for the silica, -and thus replacing, particle by particle, the carbon of the wood with -silicon, so that at length it becomes petrified into a flinty mass, so -the sarcode of a Foraminifer can in like manner abstract silica from -the surrounding water or water-soaked sediment. From some peculiarity -in the conditions of the case, however, our Protozoon usually becomes -petrified with a hydrous silicate instead of with pure silica. The -favourable conditions presented by the deep sea for the combination -of silica with bases, as indicated in the reports of the _Challenger_ -already referred to, may perhaps account in part for this. But whatever -the cause, it is usual to find fossil Foraminifera with their sarcode -replaced by such material. We also find beds of glauconite retaining -the forms of Foraminifera, while the calcareous tests of these have -been removed, apparently by acid waters. - -[Footnote 47: Berthier, quoted by Hunt.] - -One consideration which, though conjectural, deserves notice, is -connected with the food of these humble animals. They are known to feed -to a large extent on minute plants, the Diatoms, and other organisms -having silica in their skeletons or cell-walls, and consequently -soluble silicates in their juices. The silicious matter contained -in these organisms is not wanted by the Foraminifera for their own -skeletons, and will therefore be voided by them as an excrementitious -matter. In this way, where Foraminifera greatly abound, there may be -a large production of soluble silica and silicates, in a condition -ready to enter into new and insoluble compounds, and to fill the -cavities and pores of dead shells. Thus glauconite and even serpentine -may, in a certain sense, be a sort of foraminiferal coprolitic matter -or excrement. Of course it is not necessary to suppose that this is -the only source of such materials. They may be formed in other ways, -and especially by the disintegration of volcanic ashes and lapilli -in the sea-bottom; but I suggest this as at least a possible link of -connection. - -Whether or not the conjecture last mentioned has any validity, there is -another and most curious bond of connection between oceanic Protozoa -and silicious deposits. Professor Wyville Thompson reports from the -_Challenger_ soundings, that in certain areas of the South Pacific -the ordinary foraminiferal ooze is replaced by a peculiar red clay, -which he attributes to the action of water laden with carbonic -acid, in removing all the lime, and leaving this red mud as a sort -of ash, composed of silica, alumina, and iron oxide. Now this is in -all probability a product of the decomposition and oxidation of the -glauconitic matter contained in the ooze. Thus we learn that when -areas on which calcareous deposits have been accumulated by Protozoa -are invaded by cold arctic or antarctic waters charged with carbonic -acid, the carbonate of lime may be removed, and the glauconite left, or -even the latter may be decomposed, leaving silicious, aluminous, and -other deposits, which may be quite destitute of any organic structures, -or retain only such remnants of them as have been accidentally or by -their more resisting character protected from destruction.[48] In this -way it may be possible that many silicious rocks of the Laurentian -and Primordial ages, which now show no trace of organization, may be -indirectly products of the action of life. In any case it seems plain -that beds of green-sand and similar hydrous silicates may be the -residue of thick deposits of foraminiferal limestone or chalky matter, -and that these silicates may in their turn be oxidized and decomposed, -leaving beds of apparently inorganic clay. Such beds may finally be -consolidated and rendered crystalline by metamorphism, and thus a -great variety of silicated rocks may result, retaining little or no -indication of any connection with the agency of life. We can scarcely -yet conjecture the amount of light which these new facts may eventually -throw on the serpentine and other rocks of the Eozoic age. In the -meantime they open up a noble field to chemists and microscopists. - -[Footnote 48: The "red chalk" of Antrim, and that of Speeton, contain -arenaceous Foraminifera and silicious casts of their shells, apparently -different from typical glauconite, and the extremely fine ferruginous -and argillaceous sediment of these chalks may well be decomposed -glauconitic matter like that of the South Pacific. I have found these -beds, the hard limestones of the French Neocomian, and the altered -green-sands of the Alps, very instructive for comparison with the -Laurentian limestones; and they well deserve study by all interested in -such subjects.] - -When the marvellous results of recent deep-sea dredgings were first -made known, and it was found that chalky foraminiferal earth is yet -accumulating in the Atlantic, with sponges and sea-urchins resembling -in many respects those whose remains exist in the chalk, the fact was -expressed by the statement that we still live in the chalk period. -Thus stated, the conclusion is scarcely correct. We do not live in the -chalk period, but the conditions of the chalk period still exist in the -deep sea. We may say more than this. To some extent the conditions of -the Laurentian period still exist in the sea, except in so far as they -have been removed by the action of the Foraminifera and other limestone -builders. To those who can realize the enormous lapse of time involved -in the geological history of the earth, this conveys an impression -almost of eternity in the existence of this oldest of all the families -of the animal kingdom. - -We are still more deeply impressed with this when we bring into view -the great physical changes which have occurred since the dawn of life. -When we consider that the skeletons of Eozoon contribute to form the -oldest hills of our continents; that they have been sealed up in solid -marble, and that they are associated with hard crystalline rocks -contorted in the most fantastic manner; that these rocks have, almost -from the beginning of geological time, been undergoing waste to supply -the material of new formations; that they have witnessed innumerable -subsidences and elevations of the continents; and that the greatest -mountain chains of the earth have been built up from the sea since -Eozoon began to exist,--we acquire a most profound impression of the -persistence of the lower forms of animal life, and know that mountains -may be removed and continents swept away and replaced, before the least -of the humble gelatinous Protozoa can finally perish. Life may be a -fleeting thing in the individual, but as handed down through successive -generations of beings, and as a constant animating power in successive -organisms, it appears, like its Creator, eternal. - -This leads to another and very serious question. How long did lineal -descendants of Eozoon exist, and do they still exist ? We may for -the present consider this question apart from ideas of derivation -and elevation into higher planes of existence of which, in point of -fact, we have no actual evidence. Eozoon as a species and even as a -genus may cease to exist with the Eozoic age, and we have no proof -that any succeeding forms of Protozoa are its modified descendants. -Whatever the causes which produced the earliest Protozoan, they may -have continued more or less to be operative in succeeding ages. As far -as their structures inform us, they may as much claim to be original -creations as Eozoon itself. Still descendants of Eozoon may have -continued to exist, though we have not yet met with them. I should not -be surprised to hear of a veritable specimen being some day dredged -alive in the Atlantic or the Pacific. It is also to be observed that -in animals so simple as Eozoon many varieties may appear, widely -different from the original. In these the general form and habit of -life are the most likely things to change, the minute structures much -less so. We need not, therefore, be surprised to find its descendants -diminishing in size or altering in general form, while the characters -of the fine tubulation and of the canal system would remain. We need -not wonder if any sessile Foraminifer of the Nummuline group should -prove to be a descendant of Eozoon. It would be less likely that a -Sponge or a Foraminifer of the Rotaline type should originate from -it. If one could only secure a succession of deep-sea limestones -with Foraminifers, extending all the way from the Laurentian to the -present time, I can imagine nothing more interesting than to compare -the whole series, with the view of ascertaining the limits of descent -with variation, and the points where new forms are introduced. We have -not yet such a series, but it may be obtained; and as Foraminifera -are eminently cosmopolitan, occurring over vastly wide areas of -sea-bottom, and are very variable, they would afford a better test of -theories of derivation than any that can be obtained from the more -locally distributed and less variable animals of higher grade. I was -much struck with this recently, in examining a series of Foraminifera -from the Cretaceous of Manitoba, and comparing them with the varietal -forms of the same species in the interior of Nebraska, 500 miles to -the south, and with those of the English chalk and of the modern seas. -In all these different times and places we had the same species. In -all they existed under so many varietal forms passing into each other, -that in former times every species had been multiplied into several. -Yet in all, the identical varietal forms were repeated with the most -minute markings alike. Here were at once constancy the most remarkable -and variations the most extensive. If we dwell on the one to the -exclusion of the other, we reach only one-sided conclusions, imperfect -and unsatisfactory. By taking both in connection we can alone realize -the full significance of the facts. We cannot yet obtain such series -for all geological time; but it may even now be worth while to inquire, -What do we know as to any modification in the case of the primeval -Foraminifers, whether with reference to the derivation from them of -other Protozoa or of higher forms of life? - -There is no link whatever in geological fact to connect Eozoon with any -of the Mollusks, Radiates, or Crustaceans of the succeeding Palæozoic. -What may be discovered in the future we cannot conjecture; but at -present these stand before us as distinct creations. It would, of -course, be more probable that Eozoon should be the ancestor of some -of the Foraminifera of the Primordial age, but strangely enough it is -very dissimilar from all these except Cryptozoon; and here, as already -stated, the evidence of minute structure fails to a great extent, and -Eozoon Bavaricum of the Huronian age scarcely helps to bridge over the -gap which yawns in our imperfect geological record. Of actual facts, -therefore, we have none; and those evolutionists who have regarded the -dawn-animal as an evidence in their favour, have been obliged to have -recourse to supposition and assumption. - -Taking the ground of the derivationist, it is convenient to assume -(1) that Eozoon was either the first or nearly the first of animals, -and that, being a Protozoan of simple structure, it constitutes an -appropriate beginning of life; (2) that it originated from some -unexplained change in the protoplasmic or albuminous matter of some -humble plant, or directly from inorganic matter, or at least was -descended from some creature only a little more simple which had -being in this way; (3) that it had in itself unlimited capacities -for variation and also for extension in time; (4) that it tended to -multiply rapidly, and at last so to occupy the ocean that a struggle -for existence arose; (5) that though at first, from the very nature -of its origin, adapted to the conditions of the world, yet as these -conditions became altered by physical changes, it was induced to -accommodate itself to them, and so to pass into new species and genera, -until at last it appeared in entirely new types in the Cambrian fauna. - -These assumptions are, with the exception of the first two, merely -the application to Eozoon of what have been called the Darwinian laws -of multiplication, of limited population, of variation, of change -of physical conditions, and of equilibrium of nature. If otherwise -proved, and shown to be applicable to creatures like Eozoon, of course -we must apply them to it; but in so far as that creature itself is -concerned they are incapable of proof, and some of them contrary to -such evidence as we have. We have, for example, no connecting link -between Eozoon and any form of vegetable life. Its structures are such -as to enable us at once to assign it to the animal kingdom, and if we -seek for connecting links between the lower animals and plants, we have -to look for them in the modern waters. We have no reason to conclude -that Eozoon could multiply so rapidly as to fill all the stations -suitable for it, and to commence a struggle for existence. On the -contrary, after the lapse of untold ages the conditions for the life of -Foraminifers still exist over two-thirds of the surface of the earth. -In regard to variation, we have, it is true, evidence of the wide range -of varieties of species in Protozoa, within the limits of the group, -but none whatever of any tendency to pass into other groups. Nor can -it be proved that the conditions of the ocean were so different in -Cambrian or Silurian times as to preclude the continued and comfortable -existence of Eozoon. New creatures came in which superseded it, and -new conditions more favourable in proportion to these new creatures; -but neither the new creatures nor the new conditions were necessarily -or probably connected with Eozoon, any farther than that it may -have served newer tribes of animals for food, and may have rid the -sea of some of its superfluous lime in their interest. In short, the -hypothesis of evolution will explain the derivation of other animals -from Eozoon if we adopt its assumptions, just as it will in that case -explain anything else; but the assumptions are improbable, and contrary -to such facts as we know. - -Eozoon itself, however, bears some negative though damaging testimony -against evolution, and I take the liberty of repeating here a summary -of its imaginary autobiography:--"I, Eozoon Canadense, being a creature -of low organization and intelligence, and of practical turn, am no -theorist, but have a lively appreciation of such facts as I am able -to perceive. I found myself growing upon the sea-bottom, and know not -whence I came. I grew and flourished for ages, and found no let or -hindrance to my expansion, and abundance of food was always floated -to me without my having to go in search of it. At length a change -came. Certain creatures with hard snouts and jaws began to prey on -me. Whence they came I know not; I cannot think that they came from -the germs which I had dispersed so abundantly throughout the ocean. -Unfortunately, just at the same time lime became a little less abundant -in the waters, perhaps because of the great demands I myself had made, -and thus it was not so easy as before to produce a thick supplemental -skeleton for defence. So I had to give way. I have done my best to -avoid extinction; but it is clear that I must at length be overcome, -and must either disappear or subside into a humbler condition, and that -other creatures better provided for the new conditions of the world -must take my place." In such terms we may suppose that this patriarch -of the seas might tell his history, and mourn his destiny, though he -might also congratulate himself on having in an honest way done his -duty and fulfilled his function in the world, leaving it to other and -perhaps wiser creatures to dispute as to his origin and fate, while, -much less perfectly fulfilling the ends of their own existence. - -Thus our dawn-animal has positively no story to tell as to his own -introduction or his transmutation into other forms of existence. He -leaves the mystery of creation where it was; but in connection with -the subsequent history of life we can learn from him a little as to -the laws which have governed the succession of animals in geological -time. First, we may learn that the plan of creation has been -progressive, that there has been an advance from the few, low, and -generalized types of the primeval ocean to the more numerous, higher, -and more specialized types of more recent times. Secondly, we learn -that the lower types, when first introduced, and before they were -subordinated to higher forms of life, existed in some of their grandest -modifications as to form and complexity, and occupied very important -places in the economy of the world, and that in succeeding ages, when -higher types were replacing them they were subjected to decay and -degeneracy. Thirdly, we learn that while the species has a limited term -of existence in geological time, any grand type of animal existence, -like that of the Foraminifera or of the Sponges, once introduced, -continues and finds throughout all the vicissitudes of the earth some -appropriate residence. Fourthly, as to the mode of introduction of new -types, or whether such creatures as Eozoon had any direct connection -with the subsequent introduction of mollusks, worms, or crustaceans, it -is altogether silent, nor can it predict anything as to the order or -manner of their introduction. - -Had we been permitted to visit the Laurentian seas, and to study -Eozoon and its contemporary Protozoa when alive, it is plain that we -could not have foreseen or predicted from the consideration of such -organisms the future development of life. No amount of study of the -prototypal Foraminifer could have led us distinctly to the conception -of even a Sponge or a Polyp, much less of any of the higher animals. -Why is this? The answer is that the improvement into such higher types -does not take place by any change of the elementary sarcode, either in -those chemical, mechanical, or vital properties which we can study, but -in the adding to it of new structures. In the Sponge, which is perhaps -the nearest type of all, we have the movable pulsating cilium and true -animal cellular tissue, and along with this the spicular or fibrous -skeleton, these structures leading to an entire change in the mode of -life and subsistence. In the higher types of animals it is the same. -Even in the highest we have white blood-corpuscles and germinal matter, -which, in so far as we know, carry on no higher functions of life than -those of an Amœba; but they are now made subordinate to other kinds of -tissue, of great variety and complexity, which never have been observed -to arise out of the growth of any Protozoon. There would be only a -very few conceivable inferences which the highest finite intelligence -could deduce as to the development of future and higher animals. He -might infer that the foraminiferal sarcode, once introduced, might be -the substratum or foundation of other but unknown tissues in the higher -animals, and that the Protozoan type might continue to subsist side -by side with higher forms of living things as they were successively -introduced. He might also infer that the elevation of the animal -kingdom would take place with reference to those new properties of -sensation and voluntary motion in which the humblest animals diverge -from the life of the plant. - -It is important that these points should be clearly before our minds, -because there has been current of late among naturalists a loose way -of writing with reference to them, which seems to have imposed on many -who are not naturalists. It has been said, for example, that such an -organism as Eozoon may include potentially all the structures and -functions of the higher animals, and that it is possible that we might -be able to infer or calculate all these with as much certainty as we -can calculate an eclipse or any other physical phenomenon. Now, there -is not only no foundation in fact for these assertions, but it is from -our present standpoint not conceivable that they can ever be realized. -The laws of inorganic matter give no data whence any _à priori_ -deductions or calculations could be made as to the structure and -vital forces of the plant. The plant gives no data from which we can -calculate the functions of the animal. The Protozoon gives no data from -which we can calculate the specialties of the Mollusc, the Articulate, -or the Vertebrate. Nor unhappily do the present conditions of life of -themselves give us any sure grounds for predicting the new creations -that may be in store for our old planet. Those who think to build a -philosophy and even a religion on such data are mere dreamers, and have -no scientific basis for their dogmas. They are more blind guides than -our primeval Protozoon himself would be, in matters whose real solution -lies in the harmony of our own higher and immaterial nature with the -Being who is the author of all life--the Father "from whom every family -in heaven and earth is named." - - - - - _SOME GENERAL CONCLUSIONS_ - - - - - XI - - _SOME GENERAL CONCLUSIONS_ - - -It may very properly be said that many elements of uncertainty -accompany the questions discussed in the previous chapters, and that -in any case our information is too scanty to warrant any positive -conclusions respecting the origin and earliest history of living -beings. On the other hand, it is well to take stock of what we do know, -and even of what we may reasonably suppose; keeping always in view -the fact that some parts of the problem of the origin of life are at -present insoluble, and may possibly ever continue in that condition. I -may, therefore, profitably close with a summary of what at present seem -to be ultimate facts and principles in this matter, which, if we have -not yet fully attained to, we may at least keep in view as objective -points. - -If we admit that Eozoon was an animal, we may either assume that it -was the first introduced on the earth, or that there were earlier and -possibly even simpler creatures. In either case we begin the chain of -animal life with a Protozoan belonging to one of the simpler or more -generalized types of that group, and entitled to the name, both because -of its place in order of time and of rank in the development of the -animal kingdom. If we deny the claims of Eozoon, then the base of our -animal system must for the present be found in the Sponges, Worms, -Foraminifera, and Radiolarians of the Huronian, with the problematical -laminated forms allied to Cryptozoon which seem to occur even in the -Upper Laurentian. Thus in this case the miracle of creation stands -before us in a somewhat more complex form, though greatly less so than -if we had to accept the fauna of the Lower Cambrian as the oldest known. - -Under any supposition we cannot hope to get beyond a Protozoan or a -few Protozoa, and we must assume that these could perform perfectly -in their simple way those functions of assimilation, organic -growth, reproduction, sensation, and spontaneous motion, which are -characteristic of these lowest forms of life in the present world. - -It is plain, finally, that however simple we imagine this first -possessor of animal life to be, we can have no scientific evidence -of its origination either as an embryo or as an adult. If it had no -living ancestors, we are thus face to face with the problem of the -origin of animal life, either by what has been termed "Abiogenesis" of -a merely physical and fortuitous kind, or by creation. This implies -the previous production of the complex organic compound known as -"Protoplasm," which can, so far as we know, be produced only through -the agency of previously living "Protoplasm" formed by living plants. -We have, therefore, to presuppose the "Abiogenesis" or creation of -plants as predecessors of the animal; but here the same difficulty -meets us. We have next to imagine the spontaneous origin of the -structures of the "Protozoon"--its outer and inner substance, its -nucleus, its pulsating vesicle, and its pseudopods, with its protective -test, and its endowment with vital powers of locomotion, sensation, -assimilation, nutrition, and reproduction. Can we suppose that all this -could come of the chance interaction of physical causes? - -At present the production of the living from the non-living seems to -be an impossibility, and the suggestion that at some vastly distant -point of past time physical conditions may have been so different -from those at present existing as to permit spontaneous generation -is of no scientific value. But if the existence of one primitive -Protozoon be granted, what reason have we to believe that it contains -potentially the germ of all the succeeding creatures in the great chain -of life, and the power of co-ordinating these with the successive -physical changes of the geological ages, and so producing the vast and -complicated system of the animal kingdom, extending up to the present -time? In doing so, we either elevate a low form of animal life into -the role of Creator, or fall back on indefinite chance, with infinite -probabilities against us. Reason, in short, requires us to believe in -a First Cause, self-existent, omnipotent and all-wise, designing from -the first a great and homogeneous plan, of which as yet but little -has been discovered by us. Thus any rational scheme of development of -the earth's population in geological time must be, not an agnostic -evolution, but a reverent inquiry into the mode by which it pleased the -Creator to proceed in His great work. - -Regarding the matter in this way, there is legitimate scope for science -in tracing the long lines of the different types of ancient animals to -the modern period, and endeavouring to discover which of our so-called -species are original types and which are mere derivative varieties or -races. - -It is evident that nothing is gained here by assuming that the whole -geological record is but one of innumerable vast æons of æons, which -have gone on in endless succession. If the world is made to stand -on an elephant, and this on a tortoise, and this on lower forms, it -helps us not at all if the last supporter must stand on nothing. The -difficulty thus postponed only becomes greater; and at the end we have -to imagine, not only life and organization, but even matter and energy -as fortuitously originating or creating themselves, unless produced by -an Almighty Eternal Will. - -In pursuing studies of this kind, it is best for the present to content -ourselves with tracing the continuous chains of similar creatures -throughout their extension in geological time, rather than to seek for -connecting links between different lines of being. I endeavoured some -years ago to give a popular outline of this method in a little work -entitled "The Chain of Life in Geological Time."[49] - -[Footnote 49: Religious Tract Society, London; Revell Publishing Co., -New York, Chicago, and Toronto.] - -Taking, for example, the earliest Protozoa--the Foraminifera and -Radiolaria--we find two lines of being that in endless varieties, but -with little material change, extend from the earliest periods to the -present time. In successive ages they are represented by families, -genera, and species, which are regarded as distinct, and known by -different names. But these humble animals are very variable, and what -seem to us to be new types may be merely varieties of ancestral forms. -We might even affirm that, for all we know, these two great groups, -as they exist in the present ocean, are lineal descendants of those -that flourished in the Eozoic. We could not prove this, unless we were -to find somewhere a continuous succession of deep-sea deposits that -would show the gradual changes that had occurred. On the other hand, it -is hard to believe that one individual life, so to speak, could have -continued unimpaired to animate successive and increasing masses of -matter in all the vast time extending from the Eozoic to the modern. -It is also at least equally possible that the causes and conditions, -whatever they were, that produced the earliest Protozoa may have acted -again and again in later times, originating new lines of descent with -renewed vitality. - -Still, the tracing of these almost incredibly long lines of descent, -if they are such, is a proper, though difficult, subject of scientific -research, whatever may be the result. Something has been attempted in -this direction over limited portions of time; but a vast amount of -patient labour is required before certainty can be attained even in -this department of investigation. - -When, on the other hand, we turn to the question whether such lines -of creation or descent have given off branches leading to new types, -as, for instance, from Protozoa to various Crustaceans or Mollusks, -we are entirely destitute of facts, and the statement lately made -by a leading agnostic evolutionist, that "if there is any truth in -the doctrine of evolution, every class of the animal kingdom must be -vastly older than the past records of its appearance on the surface of -the globe," shows us that all the attempts to construct genealogical -trees of the descent of animals are, so far as at present known, quite -visionary. It seems, indeed, that each leading line, as we trace it -back, ends in a blind alley, just where we might suppose that it was -about to pass into another path. This is one reason of the frequent -complaints as to the imperfection of the geological record, and of the -occurrence of "missing links" between different types of being. The -only feasible explanations of this are as yet the suppositions that -the times of introduction of new types may have been unfavourable to -the preservation of their remains, or that the first representatives -of each new group were soft-bodied animals incapable of preservation, -or that they happened to be introduced in regions yet unexplored. But -such accidents could scarcely have been the rule in every case. Even in -relation to man himself, he is still man in all the deposits in which -we can find his remains, and as remote from the apes of his time, in so -far as we know, as he is from those now his contemporaries. It would -seem, in short, as if, ashamed of his humble origin, he had carefully -obliterated his tracks in ascending from his lowly parentage to the -dignity of humanity. But in this he is only following the example of -other animals, his predecessors. We may, as is now constantly done -by evolutionists, fill up these gaps by plausible conjectures; but -this is not a scientific mode of procedure, unless we are content to -regard these conjectures as working hypotheses in aid of researches yet -without result. - -It is important that general truths of this kind, impressed upon us by -our descent to the ascertained beginnings of life, should be generally -known, as counteractive to the confident statements so frequently put -forth by enthusiastic speculators and caterers of sensational popular -science. In point of fact, we still occupy the position so long ago -defined by the Apostle Paul, that "God's invisible things from the -creation of the world are clearly seen, being understood by the things -that are made, even His eternal power and divinity"; and the rational -student of nature must still be a pupil in the school of the Almighty -Maker of all things. - -Realizing this, we can learn something both as to the dignity and the -humility of our own position. On the one hand we perceive that, in -the whole chain of life, man is the only being in the likeness of the -Maker, fitted to be His deputy in the world, to understand His great -work, and to be the heir of the whole. To man alone He has proclaimed, -"I have said ye are gods, and all of you children of the Most High." To -man alone has He given that "inspiration of the Almighty" which makes -Him the interpreter of nature. On the other hand, when we consider the -long extent in time of the great chain of life before man, and along -with this the vast oceanic area inaccessible to us, yet ever since the -dawn of life teeming with living things innumerable, we find that man -is not even in this little world the only object of Divine care, and we -learn a lesson of humility and of the obligations which rest on us not -only in relation to our fellow-men, but toward our humbler companions -who share with us the care of their Father and ours. - -Finally, it is plain that scientific investigation can never bring us -within reach of the absolute origin of life, otherwise than by the -action of a creative Will. Had we stood on the earliest shore, and had -we seen living things appear in the waters where before had been merely -inorganic sand or rock, we should have known as little as we know -to-day of even the proximate causes of this new departure in nature. -If agnostics, we might have said, "this is spontaneous generation"; -but such an expression would convey no distinct idea of the nature -of the change which had occurred. It would be merely a cloak for our -ignorance. If theists, we might say, "this is creation"; but we would -have heard no audible fiat, nor seen any process or manipulation, nor -known by what subordinate agency, if any, the result was produced. We -could have given no further explanation than that of the ancient writer -who tells us that God said, "Let the waters swarm with swarmers." We -are told that when these great creative changes occurred, they were -witnessed by higher intelligences than man. "Then the morning stars -sang together, and all the sons of God shouted for joy"[50]; but -even they could perhaps know little more than we, though they might -be better able to trace the future development of the wonderful plan -commenced in the humble Protozoa and culminating in man and immortality. - -[Footnote 50: Job xxxviii. 7.] - - - - - _APPENDIX_ - - - - - _APPENDIX_ - - - * * * * * - - -A. Geological Relations of Eozoon, Archæozoon, etc. - -IN the text I have given the arrangement of the pre-Cambrian -rock-formations of Canada, as understood by me at the time of the -delivery of the lectures on which this work is based--an arrangement -which I believe will, in the main, be sustained by the work of the -future, but which cannot as yet be received as final. The work of -Logan and Murray, so far as I have had opportunity to go over their -ground, was admirable; but since their time the progress in the -settlement of the country, the extension of railways, and other means -of communication, and the opening up of mineral deposits have greatly -increased the means of obtaining information, and detailed explorations -have been in progress under the Geological Survey of Canada. At this -moment, under the new Director of the Survey, Dr. G. M. Dawson, much -work is being done in this difficult field, more especially by Dr. -Ells, Dr. Adams, and Mr. Barlow, which it may be hoped will go far -to settle finally the arrangement and distribution of pre-Cambrian -rocks in the Northern part of the American Continent. The maps and -detailed reports representing these explorations are not yet before -the public, but from some preliminary notices which have appeared in -scientific periodicals, it may be inferred that the distinction between -the fundamental gneiss, with its associated igneous products, and the -Upper Laurentian, will become greater than was supposed by Logan. The -Lowest Laurentian or Trembling Mountain series of Logan now represents -a very widely extended basement formation, not so far as can be -ascertained, composed of sedimentary rocks in a metamorphosed state, -but rather of peculiar aqueo-igneous materials, different from the -greater part of those which succeeded them, and associated with varied -and extensive igneous intrusions and _in-meltings_ like those which -Keilhau ascertained long ago in the case of similar rocks in Norway. -The Grenville series, on the other hand, may prove to be a remnant of -an overlying system, originally less extensive or bordering the older -group, and greatly attenuated by the enormous denudation which the -whole region has undergone. - -[Illustration: Fig. 60.--_Eozoon Canadense._ - -Portion of a large specimen. Nature-printed. Showing the laminæ, and -irregular cavities filled with serpentine, perhaps corresponding to the -funnels.] - - [_To face p. 296._ - -It may also be found that the beds of limestone are fewer and their -repetitions more numerous than had been supposed, and that the -Grenville series may be closely associated locally, at least, with -beds hitherto of uncertain age, or associated with the Lower Huronian. -The Huronian proper, on the other hand, may be considerably extended, -and the Kewenian and Animiké series overlying it have already been -ascertained by the Canadian Geological Survey to overlap the Huronian -and Laurentian over vast areas between the great lakes and the Arctic -sea, evidencing much submergence at the close of the Huronian age, and -opening of the Palæozoic. I have noticed in the text the apparently -wide development of deposits of this age over the area of the Rocky -Mountains of Canada, and the corresponding territories in the United -States. There would seem to be in these regions a great thickness of -unaltered sediments between the Lower Cambrian and the crystalline -rocks below, representing the Huronian and Laurentian. In these very -few fossils have yet been found, but they afford perhaps the most -promising field, next to their representatives in Newfoundland and -New Brunswick, for the discovery of the predecessors of the Olenellus -fauna, and the forms of life connecting these with those known in the -Huronian and Laurentian. [For summaries of facts on the last-mentioned -subject, see Report of Dr. G. M. Dawson on the Kamloops map-sheet, in -"Reports of Geological Survey of Canada," vol. vii. B, new series, -pp. 29 _et seq._; also Reports of Dr. C. D. Walcott, U. S. Geological -Survey, vol. xiv., Part I., pp. 103 _et seq._, and Part II., pp. 503 -_et seq._] - - * * * * * - - -B. Preservation of Organic Remains by Injection with Hydrous Silicates. - -The late Dr. T. Sterry Hunt contributed to the original paper on -Eozoon in the Journal of the Geological Society, a valuable essay on -the mineralization of fossils by serpentine, glauconite, and allied -hydrous silicates. This was in part reprinted in the notes appended -to one of the chapters of "The Dawn of Life," and the subject was -further discussed by Hunt in his invaluable work, "Chemical and -Geological Essays," and more especially in the chapter on the "Origin -of Crystalline Rocks," a chapter which every geologist deserving the -name should study with care. - -I give here some of the more important facts referred to by Hunt, and -may add that subsequent microscopic studies have familiarized me with -the occurrence of serpentine and other hydrous silicates as fillings -of the cavities of fossils of various geological ages, insomuch that I -have come to regard the occurrence of these rocks in association with -fossiliferous limestones as among the best available means to enable us -to ascertain the minute structures of shells, Foraminifera, corals, etc. - -The following remarks and analyses further illustrate Hunt's views on -the relations of these minerals, with some of the facts on which they -are based:-- - -"In connection with the Eozoon it is interesting to examine more -carefully into the nature of the matters which have been called -glauconite or green-sand. These names have been given to substances of -unlike composition, which, however, occur under similar conditions, -and appear to be chemical deposits from water, filling cavities in -minute fossils, or forming grains in sedimentary rocks of various ages. -Although greenish in colour, and soft and earthy in texture, it will -be seen that the various glauconites differ widely in composition. -The variety best known, and commonly regarded as the type of the -glauconites, is that found in the green-sand of Cretaceous age in -New Jersey, and in the Tertiary of Alabama; the glauconite from the -Lower Silurian rocks of the Upper Mississippi is identical with it -in composition. Analysis shows these glauconites to be essentially -hydrous silicates of protoxyd of iron, with more or less alumina, and -small but variable quantities of magnesia, besides a notable amount of -potash. This alkali is, however, sometimes wanting, as appears from -the analysis of a green-sand from Kent, in England, by that careful -chemist, the late Dr. Edward Turner, and in another examined by -Berthier, from the calcaire grassier, near Paris, which is essentially -a serpentine in composition, being a hydrous silicate of magnesia and -protoxyd of iron. A comparison of these last two will show that the -loganite, which fills the ancient Foraminifer of Burgess, is a silicate -nearly related in composition. - -I. Green-sand from the _calcaire grossier_, near Paris. Berthier (cited -by Beudant, "Mineralogie," ii., 178). - -II. Green-sand from Kent, England. Dr. Edward Turner (cited by Rogers, -Final Report, Geol. N. Jersey, page 206). - -III. Loganite from the Eozoon of Burgess. - -IV. Green-sand, Lower Silurian; Red Bird, Minnesota. - -V. Green-sand, Cretaceous, New Jersey. - -VI. Green-sand, Lower Silurian, Orleans Island. - -The last four analyses are by myself." - - - I. II. III. IV. V. VI. - Silica 40·0 48·5 35·14 46·58 50·70 50·7 - Protoxyd of iron 24·7 22·0 8·60 20·61 22·50 8·6 - Magnesia 16·6 3·8 31·47 1·27 2·16 3·7 - Lime 3·3 2·49 1·11 - Alumina 1·7 17·0 10·15 11·45 8·03 19·8 - Potash traces 6·96 5·80 8·2 - Soda ·98 ·75 ·5 - Water 12·6 7·0 14·64 9·66 8·95 8·5 - ---- ---- ------ ----- ------ ----- - 98·9 98·3 100·00 100·00 100·00 100·0 - -An eminent example is the Silurian limestone of Pole Hill, in New -Brunswick, collected by the late Mr. Robb, of the Geological Survey, -and referred to in the text. I cannot doubt that the silicate injecting -Crinoids and other fossils in this limestone must have been introduced -into these when still recent, and the same remark applies to the -serpentine filling a coral at Lake Chebogamong, and fragments of -corals at Melbourne, in Eastern Canada, and to the similar mineral -filling fossils in a limestone from Llangwyllog, in Wales, and in that -of Maxville, Ohio. Hunt regarded all these as coming essentially into -the same category as regard to general composition and properties. His -analysis of the minerals from Pole Hill and Llangwyllog is as follows:-- - - Pole Hill. Llangwyllog. - Silica 38·93 35·32 - Alumina 28·88 22·66 - Protoxyd of iron 18·86 } 24·12 } - Magnesia 4·25 } 6·96 } - Potash 1·69 } 1·40 } - Soda ·48 } 0·67 } - Water 6·91 11·46 - Insoluble, quartz - ------ ----- - 100·00 99·89 - -These minerals approach in composition to the jollyte of Von Kobell, -from which they differ in containing a portion of alkalies, and only -one half as much water. In these respects they agree nearly with the -silicate found by Robert Hoffman, at Raspenau, in Bohemia, where it -occurs in thin layers alternating with picrosmine, and surrounding -masses of Eozoon in the Laurentian limestones of that region;[51] -the Eozoon itself being there injected with a hydrous silicate which -may be described as intermediate between glauconite and chlorite in -composition." - -[Footnote 51: _Journ. fur Prakt. Chemie_, Bd., 106 (1869), p. 356.] - -In the Welsh specimen the silicate is of a deep green colour, except -where oxidized, and though only 3 per cent, of the whole, is sufficient -to give it an olive colour and slight serpentinous lustre. In the Pole -Hill material, the silicate amounts to 5 per cent, of the whole, and -is of a greyish colour. For some further particulars, see my Paper on -"Fossils Mineralized with Silicates" (_Journal Geological Society_, -February, 1879). - - * * * * * - - -C. Affinities of Eozoon, etc., with more Modern Forms. - -Dr. Carpenter, who in admirable papers, which I need not quote -here,[52] has illustrated in detail the structures of Eozoon, and -shown its resemblance to modern forms, places Eozoon as a generalized -type between the Nummuline and Rotaline groups of Foraminifera. It -resembles the former in its fine and complicated tubulations, and some -of the larger sessile forms of the latter in its habit of growth. -More especially, this is near to that of the genera Carpenteria and -Polytrema. In the former, more especially, there are a number of -somewhat flattened calcareous cells with perforated walls, and built -up in a conical form around a central pipe or funnel into which the -apertures of the cells open. A specimen of Carpenteria, enlarged and -having the walls of its cells thickened by a supplemental tubulated -deposit like that of Calcarina, would approach very near to Eozoon. - -[Footnote 52: I may specially refer to the following:-- - -W. B. Carpenter on _Eozoon Canadense_. _Intellectual Observer_, No. -xl., p. 300, 1865. Supplemental notes on the structure and affinities -of _Eozoon Canadense_, _Quart. Journ. Geol. Soc._, Lond. Vol. xxii., -pp. 219-228, 1866. Notes on the structures and affinities of _Eozoon -Canadense_. _Canad. Nat._, new ser., vol. ii., pp. 111-119, wood-cut, -1865. A reprint from _Quart. Journ. Geol. Soc._, Lond., 1865. Further -observations on the structure and affinities of _Eozoon Canadense_. -In a letter to the President. _Proc. Roy. Soc._, Lond., vol, xxv., -pp. 503-508, 1867. New observations on _Eozoon Canadense_. _Ann._ and -_Mag. Nat. Hist._, sen 4, vol. xiii., pp. 456-470, one plate, 1874. -Final note on _Eozoon Canadense_. _Ann._ and _Mag. Nat. Hist._, ser. -4, vol. xiv., pp. 371-372, 1874. Remarks on Mr. H. J. Carter's letter -to Prof. King on the structure of the so-called _Eozoon Canadense_. -_Ann._ and _Mag. Nat. Hist._, ser. 4, vol. xiii., pp. 277-284, with two -engravings, 1874.] - -The question of the general relation of an organism like Eozoon to -creatures known to us in the modern seas may be answered in either of -two ways:--(1) Functionally or in relation to the position of such -an animal in nature: or (2) Zoologically, or with reference to its -affinities to other animals. With reference to the first consideration, -the answer is plain. The geological function of Eozoon was that of -a collector of calcareous matter from the surrounding waters, then -probably very rich in calcium carbonate, and its role was the same with -that of the Stromatoporæ and calcareous Sponges, smaller Foraminifera -and Corals in latter times. The answer to the second aspect of the -question is less easy. An ordinary observer would at once place -Eozoon with the Stromatoporidæ or Layer-corals, which fill or even -constitute whole beds of limestone in the Cambro-Silurian, Silurian -and Devonian Periods. While, however, Eozoon has been claimed on -the highest authority for the Rhizopods, the Stromatoporæ and their -allies have been regarded as Sponges, or more recently as Hydroids -allied to the Hydractiniæ and Millepores.[53] I confess that I am not -satisfied with these interpretations. I have in my collections large -numbers of encrusting spinous forms, usually called Stromatoporæ, but -which I have long set aside as probably Hydractiniæ. There are other -forms with large vertical tubes which I have regarded as corals, -but some Stromatoporæ seem to be different from either, and I am -still disposed to regard many of them as Protozoa. Bearing in mind, -however, that the Silurian is as remote from the Laurentian on the -one hand as from the Tertiary on the other, we might be prepared to -expect that if the Layer-corals of the Silurian are divisible into -different groups, somewhat widely separated, and we have in the lower -Palæozoic the peculiar type of Cryptozoon, we may be prepared to -expect in the Laurentian much more generalized forms, less susceptible -of classification in our modern systems. If, therefore, Eozoon were -accessible to us in a living state, I should not be surprised to find -that--while perhaps more akin to the calcareous-shelled Rhizopods than -to any other modern group--it may have presented points of resemblance -to Sponges or even to Hydroids, in its skeleton and mode of growth, and -even in the arrangement of its soft parts. - -[Footnote 53: See Nicholson and Murie's able memoirs, Publications of -Pal. Soc, 1885.] - -Taking this view of its nature and relations, the genus and the -Laurentian species may be characterized as follows:-- - -_Genus_ Eozoon, _Dawson_. - -Foraminiferal skeletons, with irregular and often confluent cells, -arranged in concentric and horizontal laminæ, or sometimes piled in an -acervuline manner. Septal orifices irregularly disposed. Proper wall -finely tubulated. Intermediate skeleton with branching canals. - -Eozoon Canadense, _Dawson_. - -In inverted conical or rounded masses or thick encrusting sheets, -frequently of large dimensions. Typical structure stromatoporoid, or -with concentric calcareous walls, frequently uniting with each other, -and separating flat chambers, more or less mammillated, and spreading -into horizontal lobes and small chamberlets; chambers often confluent -and crossed by irregular calcareous pillars connecting the opposite -walls. Upper part often composed of acervuline chambers of rounded -forms. Proper wall tubulated very finely. Intermediate skeleton -largely developed, especially at the lower part, and traversed by large -branching canals, often with smaller canals in their interstices. Lower -laminæ and chambers often three millimetres in thickness. Upper laminæ -and chambers one millimetre or less. Age Upper Laurentian and perhaps -Huronian. - -_Var._ minor.--Supplemental skeleton wanting, except near the base, and -with very fine canals. Laminæ of sarcode much mammillated, thin, and -separated by very thin walls. Probably a depauperated variety. - -_Var._ acervulina.--In oval or rounded masses, wholly acervuline. Cells -rounded; intermediate skeleton absent or much reduced; cell-walls -tubulated. This may be a distinct species, but it closely resembles the -acervuline parts of the ordinary form. - -Assuming the Archæospherinæ so abundantly found in the Eozoon -limestones to be distinct organisms, and not mere germs or buds of -Eozoon, they may be thus defined:-- - - -_Genus_ Archæospherina, _Dawson_. - -A provisional genus, to include rounded solitary chambers, or -globigerine assemblages of such chambers, with the cell-wall -surrounding them tubulated as in Eozoon, or perhaps in some cases with -simple pores like those of Rotalines. They may be distinct organisms, -or gemmæ, or detached fragments of Eozoon. Some of them much resemble -the bodies figured by Dr. Carpenter, as gemmæ or ova and primitive -chambers of Orbitolites. They are very abundant on some of the strata -surfaces of the limestones at Côte St. Pierre. Age Upper Laurentian. - -I may add here the characters of Matthew's new genus, Archæozoon, as -given by him:-- - - -_Genus_ Archæospherina, _Matthew_. - -Skeleton composed of thin concentric laminæ convex upward, and having -between them a granular layer filled with minute branching canals. - -Archæospherina Acadiense, Matthew. - -Habit of growth cylindrical in masses or groups, budding upward. The -microscopic characters are thus given by Matthew[54]:-- - -"The structures appear to be allied more closely to Cryptozoon than to -Eozoon. The microscopic structure is most easily recognised in the -earthy (as distinguished from the calcareous) layers, and consists -of minute branching canals. Under a one-inch objective the smaller -canals have the appearance of minute threads, which run sometimes for a -distance of two millimetres without branching. The larger canals branch -more frequently and are more sinuous. The canals cross and anastomose -with each other; they run chiefly at right angles to the axis of the -fossil, and appear to branch most in going outward from the centre. -More rarely they ascend from the earthy to the calcareous layer, -branching upward." - -[Footnote 54: Bulletin No. ix., Nat. Hist. Soc of New Brunswick, 1890.] - -In limestone of the Upper Laurentian, near St. John, New Brunswick. - - * * * * * - - -D. Cryptozoon. - -The description above given of Archæozoon very naturally leads us to -consider the allied Cambrian and pre-Cambrian forms known as Cryptozoon. - -This remarkable and problematical type was first described by Prof. -James Hall in the Appendix to his Annual Report of 1882 (No. 26). It -is a large massive organism, occurring abundantly on the surface of a -limestone of Calciferous (Upper Cambrian) age at Greenfield, Saratoga -County, New York. The individuals sometimes attain a diameter of two -feet, and are often surrounded by smaller specimens apparently budding -off from them. Like Stromatoporæ, they consist of concentric laminæ, -but these are concave upward, giving a bowl-shaped form to the summits -of the individuals. Prof Hall describes them as "made up of irregular -concentric laminæ of greater or less density, and of very unequal -thickness. The substance between the concentric lines in well-preserved -specimens is traversed by numerous minute irregular canaliculi which -branch and anastomose without regularity. The central portion of -the masses is usually filled with crystalline granular and Oolitic -material, and many specimens show the intrusion of these extraneous and -inorganic substances between the laminæ." - -Professor Hall having kindly presented some good specimens to the Peter -Redpath Museum, I have had sections made, and have thus been able to -verify his description, and to compare the structures with those of -some of the more ancient Stromatoporoid specimens in our collections, -including the Archæozoon from New Brunswick, of which Mr. Matthew -has presented a fine slab to the Museum. I have also, through the -kindness of Professor Winchell, been enabled to compare these with his -_Cryptozoon Minnesotense_, and Dr. Walcott has added specimens of his -Stromatoporoid forms from the pre-Cambrian beds of Arizona. It would -appear from these and other specimens in our collections from the -Cambrian and older Ordovician beds, that we have here an ancient type -of Stromatoporoid organism in which the original laminæ seem to have -been thin and coriaceous, without apparent pores or pillars connecting -them with each other, but having between them relatively-thick layers -of fine fragmental matter penetrated by numerous irregularly tortuous -and branching tubes. The laminæ often present a carbonaceous or -chitinous appearance, though frequently replaced by mineral matter, -and the intervening layers show both a calcareous and carbonaceous -substance, with much fine silicious sand often as rounded grains, -and apparently some dolomitic granules. The tubules seem destitute -of any distinct wall, otherwise the whole would resemble on a large -scale the nodular and laminated masses of _Girvanella_, which Wethered -has described as surrounding organic fragments in Silurian and -Carboniferous and Jurassic limestones in England.[55] - -[Footnote 55: British Association, Liverpool meeting, 1896.] - -The _Streptochetus_ of Seely from the Chazy limestone[56] is evidently -very near to Girvanella, if not generically identical, and I have a -similar species from the Lower Cambrian pebbles in the conglomerates -of the Quebec group. In all these forms, however, the thicker or -intermediate laminæ seem to consist wholly of definite convoluted -tubes, whereas in Cryptozoon the tubes, or tubular perforations, are -separated by a mass of material which in the best preserved specimens -seems to consist of a fibrous stroma including calcareous and silicious -particles. It seems doubtful to what class of beings such a structure -should be referred; but whatever its nature, it evidently had great -powers of growth, and seems to be a very ancient form of life. - -[Footnote 56: _Amer. Journ. of Science_, 1885. See Nicholson, "Manual -of Palæontology," ed. of 1889.] - -One of the species similar in structure to Hall's type, but budding -out into turbinate branches, was discovered by Mr. E. T. Chambers, of -Montreal, in the Ordovician limestone of Lake St. John, and has been -named _C. boreale_. It differs in structure from Hall's species in -having the tubes less tortuous and more nearly parallel to the laminæ. -In its outline it reminds one of the problematical Eozoon from the -Hastings group at Tudor, Ontario, referred to in the text. - -Should time permit, I hope to have all the specimens in our collections -illustrating this interesting and primitive type examined and -described. In the meantime I may merely remark that a near modern -analogue would seem to be the gigantic arenaceous Foraminifer _Neusina -Agassizi_, Goës, dredged by Alexander Agassiz in the Pacific, and -described in the Bulletin of the Museum of Comparative Zoology (Vol. -xxiii., No. 5, 1892). The modern form, it is true, is flat and -foliaceous; but some of the old species approach to this shape, and -if we suppose the little cells of Neusina to represent the tubes of -Cryptozoon, and the carbonaceous matter of the latter to be the remains -of the chitinous stroma seen in some specimens, the general resemblance -will be very close. - -The whole subject of these peculiar Stromatoporoid forms extending -from the Upper Cambrian to the Laurentian, deserves a full and careful -investigation, for which I am endeavouring to collect material. - - * * * * * - - -E. Receptaculites and Archæocyathus. - -In "The Dawn of Life" (1875), reference was made to the singular and -complicated organisms of the Upper Cambrian and Ordovician systems -known as Receptaculites, which at that time was generally regarded as -foraminiferal, and is still placed by Zittel, in his great work on -Palæontology, among forms doubtfully referable to that group. It has -also been referred to Sponges, though on very uncertain grounds. It has -not, however, so far as I am informed, been traced any farther back -than the Upper Cambrian (Calciferous), and no structural links are -known to connect it with either Eozoon or Archæozoon. For this reason -it was omitted in the text; but I think it well to mention it here, and -to direct attention to it as possibly one of the complex Protozoa which -may be traced far back toward the beginnings of life.[57] - -[Footnote 57: Billings, "Palæozoic Times."] - -Another primitive and generalized genus mentioned in the text is -_Archæocyathus_ of Billings, whose headquarters seem to be in the Lower -Cambrian, and which may probably be traced farther back. - -Mr. Billings described the genus in his "Report on Canadian Fossils" -(1861-64), taking _A. profundus_, from the Lower Cambrian of L'Anse à -Loup, on the Labrador coast, in the first instance, as the type. - -A few years later, my attention was attracted to this species by -specimens presented to me by Mr. Carpenter, a missionary on the -Labrador coast, and which Mr. Billings kindly permitted me to compare -with his specimens in the Museum of the Geological Survey, collected -by the late Mr. Richardson, at L'Anse à Loup, in Labrador, in what -were then called Lower Potsdam rocks. Slices of the specimens were -made for the microscope, when it appeared that, though they had -the general aspect of turbinate corals, like Petraia, etc., they -were quite dissimilar in structure, more especially in their porous -outer and inner walls and septa (see Fig. 5, p. 35). Yet they could -scarcely be referred to the group of porous corals known in much later -formations and in the modern seas. Nor could they be referred with -much probability to Sponges, as they were composed of solid calcareous -plates, which, as was evident from their textures, could not have been -originally spicular. One seemed thus shut up to the conclusion that -their nearest alliance was with Foraminifera, and if so, they were -very large and complex forms of that group, consisting of perforated -chambers arranged around a central cavity. I accordingly mentioned them -in this connection in 1875, not as closely related to Eozoon, but as -apparently showing the existence of very complex foraminiferal forms in -the Lower Cambrian. - -The specimens thus noticed were altogether calcareous, and were of -the species named _A. profundus_ by Mr. Billings. He had, however, -referred to the same genus silicified specimens from a later formation, -the Calciferous (Upper Cambrian) at Mingan, under the name _A. -Minganensis_, which were subsequently found to be associated with -spicules resembling those of lithistid sponges, and which proved to -be very different from the Lower Cambrian form, and are now referred -to a different genus. The subject had thus become involved in some -confusion, and was left in this state by Mr. Billings on his death. -I therefore asked my friend, Dr. Hinde, of London, to re-examine my -specimens, and at the same time those of the Geological Survey were -placed in his hands by Mr. Whiteaves. Hinde also obtained specimens -from Lower Cambrian rocks in Sardinia, where they seem to be abundant, -and from Spain. He states the results of his examinations very fully -in a paper in the Journal of the _Geological Society of London_.[58] He -retains the original name for the older and calcareous form from L'Anse -à Loup, separating from it, however, another form, _A. Atlanticus_ -of Billings's, which is destitute of distinct radiating septa and -acervuline, like the lower part of _A. profundus_. This he names -_Spirocyathus_. The Mingan species he places with Sponges under the -generic name, _Archæoscyphia_. In this Walcott substantially agrees -with Hinde in his "Memoir on the Lower Cambrian Fauna." Both seem to -refer Archæocyathus to corals, though admitting its very exceptional -and anomalous structure. I think, however, we may still be allowed to -entertain some doubts as to the reference to corals, more especially -as the skeleton does not seem to have consisted of aragonite, but of -ordinary calcite, like that of the Foraminifera. It is in any case a -primitive form which seems to be dying out in the Lower Cambrian, and -we may hope that it may be traced into the pre-Cambrian, and may form a -link connecting the Palæozoic with the Eozoic faunas. In my description -of it in "The Dawn of Life" in 1875, I used the following terms:--"To -understand Archæocyathus, let us imagine an inverted cone of carbonate -of lime from an inch or two to a foot in length, with its point planted -in the mud in the bottom of the sea, while its open cup extends upward -into the clear water. The lower part buried in the bottom is composed -of an irregular network of thick calcareous plates, enclosing chambers -communicating with one another. Above this, where the cup expands, its -walls are made up of inner and outer plates, perforated with numerous -round pores in vertical rows, and connected with each other by vertical -partitions also perforated, so as to establish a free communication -of the enclosed radiating chambers with each other, as well as with -the water within and without. Such a structure might no doubt serve as -a skeleton for a coral of somewhat peculiar internal structure, but -it might just as well accommodate a protozoan with chambers for its -sarcode, and pores for emission of pseudopods, both outwardly and by -means of the interior cup, which in that case would represent a funnel -like that of Carpenteria, or one of the tubes of Eozoon." - -[Footnote 58: Vol. xlv., 1889, pp. 125 _et seq._] - -On the whole, when we consider the magnitude and synthetic character -of such forms as Cryptozoon, Receptaculites, and Archæocyathus, -and their association with generalized types of Crustaceans and -Brachiopods, we can scarcely fail to perceive that at the base of the -Palæozoic we are leaving the reign of the higher marine invertebrates, -and entering on a domain where lower and probably Protozoan forms must -be dominant, and so are getting at least within calculable distance of -the beginnings of life. - - * * * * * - - -F. Pre-Geological Evolution. - -Reference is incidentally made in the text to the doctrine implied in -the old notion of successive cataclysms and renewals of the earth, -held by some ancient mythologies and philosophies, and revived in a -slightly different form by Mr. Herbert Spencer, in connection with the -requirements of the Darwinian evolution by natural selection. This -primitive idea was illustrated at considerable length by Professor -Poulton in his address as President of the Zoological Section of the -British Association at its meeting in Liverpool (September, 1896). In -this new and ably presented form, it deserves some notice as excluding -the hope of our finding the beginnings of life in any geological -formations at present known. - -Professor Poulton refers to the argument used by Lord Salisbury, -in his address at the Oxford meeting, on the insufficiency of time -for the requirements of the Darwinian evolution. He then discusses -the estimates based by Lord Kelvin and Professor Tait on physical -considerations, and dismisses them as altogether inadequate, though -he admits that Professor George Darwin agrees with Lord Kelvin in -regarding 500 millions of years as the maximum duration of the life of -the sun. - -He next takes up the estimates of geologists, and rather blames as too -modest those who ask for the longest time, say 400 millions of years, -for the duration of the habitable earth. He evidently scarcely deems -worthy of notice the more moderate demands of many eminent students of -the earth, who have based far lower estimates on more or less reliable -data of denudation and deposition, and on the thickness of deposits in -connection with their probable geographical extent. - -He then proceeds to consider the biological evidence, and dwells on -the number of distinct types represented as far back as the Lower -Cambrian. Independently of the interpretations and explanations -of this great fact, the numerous types there represented, and the -persistence of some of them to the present day, give an almost -overwhelming impression of the vast duration of organisms in time. In -connection with the supposed slow and gradual process of evolution, -this naturally leads to the conclusion that "the whole period in which -the fossiliferous rocks were laid down must be multiplied several times -for this later history (that of the higher groups of animals alone). -The period thus obtained requires to be again increased, and perhaps -doubled for the earlier history." Ordinary geologists naturally stand -aghast at such demands, and inquire if they are seriously put forth, -and if it would not be wise to hesitate before accepting a theory on -behalf of which such drafts on time must be made. The late Edward -Forbes once humorously defined a geologist to be "an amiable enthusiast -who is happy and content if you will give him any quantity of that -which other men least value, namely, past time." But had this great -naturalist lived to "post-Darwinian" times, he might have defined a -Darwinian biologist to be an insatiable enthusiast, who feels himself -aggrieved if not supplied with infinity itself, wherein to carry on -the processes of his science. Seriously however, the necessity for -indefinitely protracted time does not arise from the facts, but from -the attempt to explain the facts without any adequate cause, and to -appeal to an infinite series of chance interactions apart from a -designed plan, and without regard to the consideration, that we know of -no way in which, with any conceivable amount of time, the first living -and organized beings could be spontaneously produced from dead matter. -It is this last difficulty which really blocks the way, and leads to -the wish to protract indefinitely an imaginary process, which must end -at last in an insuperable difficulty. - -Were Evolutionists content to require a reasonable time for the -development of life, and to assign this to an adequate cause, they -might see in the reduction of living things in the pre-Cambrian ages to -few and generalized or synthetic types, evidence of an actual approach -to the beginnings of life, and beyond this to a condition of the earth -in which life would be impossible. - - * * * * * - - -G. Controversies Respecting Eozoon. - -In the text (Chapter IX.) I have referred in a cursory manner to these, -but have felt that it would be unprofitable to fight the old battles -over again, except in so far as the objections raised have suggested -new lines of study and investigation. The old objections of Messrs. -Rowney, King and Carter were conclusively replied to by the late Dr. -Carpenter. The later criticisms of Möbius in his elaborated memoir -in "Palæontographica" were in appearance more formidable; but he had -evidently entered on the question with imperfect material, and a very -defective conception of its extent and meaning. His treatment of it was -also marked by unfairness to those who had previously worked at the -subject, and by that narrow specialism and captious spirit for which -German naturalists are too deservedly celebrated. The difficulties he -raised were met at the time, more especially in articles by the present -writer in the American _Journal of Science_, and in the Canadian -Naturalist. Möbius, I have no doubt, did his best from his special -and limited point of view; but it was a crime which science should -not readily pardon or forget, on the part of editors of the German -periodical, to publish and illustrate as scientific material a paper -which was so very far from being either fair or adequate. - -The later objections of Gregory and Lavis are open to similar criticism -as imperfect and partial, and as confounding Eozoon with mineral -structures which previous writers had carefully distinguished from it. -I have stated these points in letters to _Nature_ and to the Council -of the Dublin Academy, and have also re-stated the evidence bearing on -the animal nature of Eozoon in a series of papers in the Geological -Magazine for 1895. I may add here, as apposite to the present condition -of the matter, a few remarks referring to the appearance of Eozoon -in Dr. Dallinger's new edition of Carpenter's great work on the -Microscope,[59] and more especially to his retaining unchanged the -description of _Eozoon Canadense_, as a monument of an important -research up to a certain date, while adding a note with reference to -the later criticisms of Mr. Gregory. - -[Footnote 59: _Nature_, March 17, 1892.] - -Dr. Carpenter devoted much time to the study of Eozoon, and brought -to bear on it his great experience of foraminiferal forms, and his -wonderful powers of manipulating and unravelling difficult structures. -After having spent years in studying microscopic slices of Eozoon and -the limestones in which it occurs, I have ever felt new astonishment -when I saw the manner in which, by various processes of slicing and -etching, and by dexterous management of light, he could bring out -the structure of specimens often very imperfect. Not long before Dr. -Carpenter's death, I had an opportunity to appreciate this in spending -a few days with him in studying his more recently acquired specimens, -some of them from my own collections, and discussing the new points -which they exhibited, and which unhappily he did not live to publish. -Some of these new facts, in so far as they related to specimens in our -cabinet here, have since that time been noticed in my _résumé_ of the -question in the "Memoirs of the Peter Redpath Museum," 1888. - -Those who know Dr. Carpenter's powers of investigation will not be -astonished that later observers, without his previous preparation -and rare insight, and often with only few and imperfect specimens, -should have failed to appreciate his results. One is rather surprised -that some of them have ventured to state with so great confidence -their own negative conclusions in a matter of so much difficulty, -and requiring so much knowledge of organic structures in various -states of mineralization. For myself, after working fifty years at -the microscopic examination of fossils and organic rocks, I feel more -strongly than ever the uncertainties and liabilities to error which -beset such inquiries. - -As an illustration in the case of Eozoon: since the publication of my -memoir of 1888, which I had intended to be final and exhaustive as -to the main points in so far as I am concerned, I have had occasion -to have prepared and to examine about 200 slices of Eozoon from new -material; and while most of these have either failed to show the minute -structures or have presented nothing new, a few have exhibited certain -parts in altogether unexpected perfection, and have shown a prevalence -of injection of the canal system by dolomite not previously suspected. -I have also observed that unsuitable modes of preparation, notably some -of those employed in the preparation of ordinary petrological slices, -may fail to disclose organic structures in crystalline limestones when -actually present. Since that publication also, the discoveries of Mr. -Matthew in the Laurentian of New Brunswick, and the further study of -the singular Cambrian forms of the type of Cryptozoon, have opened up -new fields of inquiry. - -I think it proper to state, in reference to Dr. Dallinger's footnote -on the recent paper of Mr. Gregory, that it must not be inferred from -it that Mr. Gregory had access to my specimens from Madoc and Tudor, -though he no doubt had excellent material from the collections of -the Canadian Geological Survey. It might also be inferred from this -note that I have regarded the Madoc and Tudor specimens as "Lower -Laurentian." The fact is, that I was originally induced in 1865, by -the belief of Sir W. E. Logan at that time that these rocks were -representatives in a less altered state of the middle part of the -Laurentian, to spend some time at Madoc and its vicinity in searching -for fossils, but discovered only worm-burrows, spicules, and fragments -of Eozoon, which were noticed in the _Journal of the Geological -Society_ for 1866. (The more complete specimen from Tudor was found by -Vennor in 1866.) On that occasion I satisfied myself fully that the -beds are much older than the Cambro-Silurian strata resting on them, -unconformably; but I felt disposed to regard them as more probably -of the age of some parts of the Huronian of Georgian Bay, which I had -explored with a similar purpose under Logan's guidance in 1856. - -[In my subsequent notice of the Tudor specimens in "The Dawn of Life," -in 1875, I referred to their age as "Upper Laurentian or Huronian"; -and I may add, that while it is certain that the beds containing them -are pre-Palæozoic, their place in the Eozoic period is still not -precisely determined. Work is, however, now in progress which it is -hoped may finally settle the age of the "Hastings group" and the old -rocks associated with it. I may add that the specimen of Cryptozoon -discovered by Mr. Chambers, and of which a portion is represented -in the Frontispiece, seems to me to throw a new light on the Tudor -specimen. It shows in any case the survival of Cryptozoa similar -in form and general appearance to that specimen, as late as the -Cambro-Silurian or Ordovician.] - - * * * * * - - -H. Notes to Appendix, December, 1896. - -While this work was going through the press, I have received the Report -of the U.S. Geological Survey for 1894-95, containing the elaborate -Memoir of C. R. Van Hise on the pre-Cambrian Geology of North America. -It is a very valuable contribution to the literature of this difficult -subject, and will constitute a standard book of reference: though I -think the use of the term "Algonkian" for groups of beds which are in -part basal Palæozoic and in part Eozoic or Archæan is to be deprecated, -and scarcely sufficient importance is attached to the labours of the -early Canadian explorers in this field. - -In the past summer I was enabled to spend a few days, with the -assistance of my friend Mr. H. Tweeddale Atkin, of Egerton Park, Rock -Ferry, in examining the supposed pre-Cambrian rocks of Holyhead Island -and Anglesey. Fossils are very rare in these beds. As Sir A. Geikie -has shown, the quartzite of Holyhead is in some places perforated with -cylindrical worm-burrows, and in the micaceous shales there are long -cylindrical cords, which may be algæ of the genus _Palæochorda_, and -also bifurcating fronds resembling _Chondrites_; but I saw no animal -fossils. I have so far been unable to discover organic structure in -the layers of limestone associated with apparently bedded serpentine -in the southern part of Holyhead Island. In central Anglesey there -are lenticular beds of limestone and dolomite associated with -pre-Cambrian rocks, which Dr. Callaway regards as probably equivalent -to the Pebidian of Hicks. In these there are obscure traces of organic -fragments; and in one bed near Bodwrog Church I found a rounded -laminated body, which may be an imperfectly preserved specimen of -Cryptozoon, or some allied organism. The specimens collected have not, -however, been yet thoroughly examined. These and other pre-Cambrian -deposits in Great Britain correspond in their testimony, with the -Eozoic rocks of North America, as to the small number and rarity of -fossil remains in the formations below the base of the Palæozoic, and -the consequent probability that in these formations we are approaching -to the beginning of life on our planet; though there is still reason -to hope that additional oases of life may be found in these deserts -of the pre-Palæozoic. Such rare intervals of fertility should be the -more valued when the labours of so many skilled observers have proved -so meagre in their results in comparison with the great extent and -thickness of the beds which have been explored. - - - - - INDEX - - - PAGE - - Adams on composition of Laurentian schists 108 - ---- his work on Laurentian stratigraphy 296 - Animals, Cambrian, classes of 7, 11 - ---- pre-Cambrian 53 - ---- Huronian 67 - ---- Grenvillian 73, 303 - Antiquity, relative 6 - Aquatic animals, permanence of 13 - Aragonite in fossils 117 - Archæocyathus 35, 315 - Archæozoon 214, 309 - - Barlow, his explorations 296 - Bavaria, Eozoon of 71 - Beecher on limbs of Trilobites 25 - Bicknell on Eozoon 141 - Billings on Eozoon 137 - ---- on Receptaculites 315 - ---- on Archæocyathus 316 - ---- on Signal Hill fossils 54 - Bonney on Côte St. Pierre 142 - Burbank on Chelmsford Eozoon 141 - - Calcarina 186 - Calumet, Grand, Eozoon of 130 - Canals of Eozoon 133 - Cambrian, life of Early 17 - ---- geography of the 18 - Carbon in Laurentian limestone 93 - Carpenter, Dr., on Eozoon 137, 303, 324 - Cayeux on Huronian fossils 68 - Chambers, Mr. E. T. 313 - Chrysotile, veins of 161, 239 - Cœnostroma 174 - Colorado cañon 56 - Controversies respecting Eozoon 324 - Corals, history of 32 - Côte St. Pierre 88, 91 - Cryptozoon 36, 56, 310 - - Dallinger, note on Eozoon 325 - Dawson, Dr. G. M. 66, 295 - - Ells, Dr. 217, 296 - Eozoon, its discovery 73, 125 - ---- its general form 149 - ---- its mode of occurrence 90 - ---- its state of preservation 111 - ---- its laminæ and chambers 152, 157 - ---- its canals and tubuli 133, 138, 158, 160 - ---- its funnels 152 - ---- its minute granular structure 133 - ---- its characters and affinities 307 - ---- objections to its animal nature 221 - ---- acervuline specimens 203 - ---- in various places 141, 233 - ---- Bavarian species 71, 213 - ---- Tudor specimens 68 - ---- fragments of, in limestones 183 - Eozoon, restoration of 327 - Eozoic time as a geological age 76 - Etcheminian system 48 - ---- fossils of 54 - Evolution, pre-geological 320 - - Foraminifera, notice of modern 175 - ---- Etcheminian 59 - ---- Huronian 71 - ---- Laurentian, etc. 303 - Fossils, how mineralized 111 - - Glauconite, mineralizing fossils 217, 298 - Granular structure in Eozoon 165 - Graphite of the Laurentian 93 - Gregory on Eozoon 235, 325 - Grenvillian series 39 - Gresley on Huronian worms 68 - Gümbel on European Eozoon 71, 213 - - Hall, Dr. James, on Cryptozoon 36, 310 - Hanford Brook, section at 51 - Hastings series (Huronian ?) 67 - Hinde on Archæocyathus 34, 317 - Hunt, Dr. Sterry, on indications of life 97 - ---- on silicates in fossils 298 - Huronian system 65 - Hymenocaris 27 - - Jones, T. Rupert, on Eozoon 75, 137 - Jullien on Eozoon 235 - - Kewenian or Kewenawan series 48 - King, Prof, on Eozoon 221 - Laurentian system 71 - ---- its limestones 92 - Lavis, Dr. Johnson, on Eozoon 235, 325 - Life in Early Cambrian 17 - ---- in pre-Cambrian 50 - ---- in Huronian 65 - ---- in Laurentian 71 - Limestones of Laurentian 92 - Logan, Sir W., on Eozoon 129 - Loganite in Eozoon 128 - Long Lake, Specimens from 190, 208 - Lowe as explorer 131, 141 - - Map of Laurentian America 85 - ---- Grenville limestone 88 - Matthew, Dr., on Archæozoon 214, 309 - ---- on Etcheminian 48, 51, 54 - McMullen as explorer 128 - Möbius on Eozoon 161, 162 - Murray on Signal Hill beds 53 - - Nummulite 163, 186 - - Objections 221 - Ocean of Cambrian 18, 21 - ---- of Laurentian 85 - Olenellus zone 20 - - Petite Nation 141 - Pole Hill, specimen from 118 - Pre-Cambrian life 47 - Pre-Cambrian rocks in Canada 76 - Pre-geological evolution 320 - Pre-Palæozoic life 216 - Pyroxene in Eozoon 167, 169 - - Receptaculites 315 - Robb, Pole Hill specimens 301 - - Serpentine, mineralizing fossils 147 - ---- different origins of 167, 171 - Signal Hill series 53 - Silicates, mineralizing fossils 217, 298 - Spines, use of 30 - Stromatoporæ 173 - St. Pierre, Côte 88, 91 - - Table of the history of life 2 - ---- of pre-Cambrian formations 76 - Triarthrus 25 - Tubuli of Eozoon 60, 61, 159 - - Van Hise on pre-Cambrian 66, 329 - Varieties of Eozoon 107, 202 - Vennor referred to 69 - - Walcott on Lower Cambrian 40, 62 - ---- on fossils, Colorado Cañon 57 - Weston, Mr., referred to 131 - White, Prof. C. A., on chronology of life 7 - Wilson, Dr., referred to 127 - Worm-burrows in Huronian 67 - Worm-trails in Lower Cambrian, etc. 40, 43 - - * * * * * - - -Transcriber Note - -In order to accommodate placement of illustrations and footnotes, many -paragraphs were split where it seemed reasonable. Minor typos were -corrected. A web search shows that the anchorless Footnote on page -139 appears to reference the quoted text on page 140. Therefore, the -Footnote was placed after the quoted text. - -On page 174, Footnote 36 referred twice to Figure 8 and to a -"Microscopic slice" as Figure 61 (which does not exist). It is assumed -the intent was to refer to Figures 7, 7a, 8 and 59 and has been altered -to point to those figures. 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