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diff --git a/old/3772-h/files/ch16.html b/old/3772-h/files/ch16.html new file mode 100644 index 0000000..2ad1d10 --- /dev/null +++ b/old/3772-h/files/ch16.html @@ -0,0 +1,1499 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!--saved from url=(0036)http://../Lyell/The Student's Elements of Geology --> +<html> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org"> +<title>The Student's Elements of Geology: Title</title> +<meta content="text/html; charset=iso-8859-1" http-equiv= +"Content-Type"> +<meta content="MSHTML 5.00.2919.6307" name="GENERATOR"> +<link rel="stylesheet" href="geology.css" type="text/css"> +</head> +<body> +<p><b>The Student’s Elements of Geology</b></p> + +<hr> +<p class="page"><a name="page 250">[ 250 ]</a></p> + +<p> </p> + +<center><b>Chapter XVI</b><br> +<br> +EOCENE FORMATIONS.</center> + +<p class="intro">Eocene Areas of North of Europe. — Table of +English and French Eocene Strata. — Upper Eocene of England. +— Bembridge Beds. — Osborne or St. Helen’s Beds. +— Headon Series. — Fossils of the Barton Sands and +Clays. — Middle Eocene of England. — Shells, +Nummulites, Fish and Reptiles of the Bracklesham Beds and Bagshot +Sands. — Plants of Alum Bay and Bournemouth. — Lower +Eocene of England. — London Clay Fossils. — Woolwich +and Reading Beds formerly called “Plastic Clay.” +Fluviatile Beds underlying Deep-sea Strata. — Thanet Sands. +— Upper Eocene Strata of France. — Gypseous Series of +Montmartre and Extinct Quadrupeds. — Fossil Footprints in +Paris Gypsum. — Imperfection of the Record. — Calcaire +Silicieux. — Gres de Beauchamp. — Calcaire Grossier. +— Miliolite Limestone. — Soissonnais Sands. — +Lower Eocene of France. — Nummulitic Formations of Europe, +Africa, and Asia. — Eocene Strata in the United States. +— Gigantic Cetacean.</p> + +<p><b>Eocene Areas of the North of Europe.</b>—The strata +next in order in the descending series are those which I term +Eocene.</p> + +<center><img src="../images1/fig164.jpg" width="348" height="306" alt= +"Fig. 164: Map of the principal Eocene areas of North-western Europe."> +</center> + +<p>In the map (Fig. 164) the position of several Eocene areas in +the north of Europe is pointed out. When this map was constructed I +classed as the newer part of the</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 251">[ 251 ]</a></p> + +<p>Eocene those Tertiary strata which have been described in the +last chapter as Lower Miocene, and to which M. Beyrich has given +the name of Oligocene. None of these occur in the London Basin, and +they occupy in that of Hampshire, as we have seen at <a href= +"ch15.html#page 244">p. 244</a>, too insignificant a superficial +area to be noticed in a map on this scale. They fill a larger space +in the Paris Basin between the Seine and the Loire, and constitute +also part of the northern limits of the area of the Netherlands +which are shaded in the map.</p> + +<p>It is in the northern part of the Isle of Wight that we have the +uppermost beds of the true Eocene best exhibited—namely, those +which correspond in their fossils with the celebrated gypsum of the +Paris basin before alluded to, <a href="ch15.html#page 231">p. +231</a> (see Table, p. 252). That gypsum has been selected by +almost all Continental geologists as affording the best line of +demarkation between the Middle and Lower Tertiary, or, in other +words, between the Lower Miocene and Eocene formations.</p> + +<p>In reference to the Table I may observe, that the correlation of +the French and English subdivisions here laid down is often a +matter of great doubt and difficulty, notwithstanding their +geographical proximity. This arises from various circumstances, +partly from the former prevalence of marine conditions in one basin +simultaneously with fluviatile or lacustrine in the other, and +sometimes from the existence of land in one area causing a break or +absence of all records during a period when deposits may have been +in progress in the other basin. As bearing on this subject, it may +be stated that we have unquestionable evidence of oscillations of +level shown by the superposition of salt or brackish-water strata +to fluviatile beds; and those of deep-sea origin to strata formed +in shallow water. Even if the upward and downward movements were +uniform in amount and direction, which is very improbable, their +effect in producing the conversion of sea into land or land into +sea would be different, according to the previous shape and varying +elevation of the land and bottom of the sea. Lastly, denudation, +marine and subaërial, has frequently caused the absence of +deposits in one basin of corresponding age to those in the other, +and this destructive agency has been more than ordinarily effective +on account of the loose and unconsolidated nature of the sands and +clays.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 252">[ 252 ]</a></p> + +<center>TABLE OF ENGLISH AND FRENCH EOCENE STRATA.<br> + <small>UPPER EOCENE</small></center> + +<center> +<table border="0" cellspacing="6" cellpadding="0" summary= +"Upper, Middle, and Lower eocene strata: left side is English subdivisions, right side is French equivalents."> +<tr> +<td align="center">English subdivisions</td> +<td align="center">French equivalents</td> +</tr> + +<tr> +<td align="left" valign="top">A.1. Bembridge series, Isle of Wight, +p. 252.</td> +<td align="left" valign="top">A.1. Gypseous series of Montmartre, +<a href="page 270">p. 270.</a></td> +</tr> + +<tr> +<td align="left" valign="top">A.2. Osborne or St. Helen's series, +Isle of Wight, <a href="page 255">p. 255.</a></td> +<td align="left" valign="top">A.2 and 3. Calcaire siliceux, or +Travertin Inférieur, <a href="page 273">p. 273.</a></td> +</tr> + +<tr> +<td align="left" valign="top">A.3. Headon series, Isle of Wight, <a +href="page 255">p. 255.</a></td> +<td align="left"> </td> +</tr> + +<tr> +<td align="left" valign="top">A.4. Barton series. Sands and clays +of Barton Cliff, Hants, <a href="page 258">p. 258.</a></td> +<td align="left" valign="top">A.4. Grès de Beauchamp, or +Sables Moyens, <a href="page 273">p. 273.</a></td> +</tr> + +<tr> +<td colspan="2" align="center"><small>MIDDLE EOCENE</small></td> +</tr> + +<tr> +<td align="left" valign="top">B.1. Bracklesham series, <a href= +"page 259">p. 259.</a></td> +<td align="left" valign="top">B.1. Calcaire Grossier <a href= +"page 274">p. 274</a></td> +</tr> + +<tr> +<td align="left" valign="top">B.2. Alum Bay and Bournemouth beds, +<a href="page 259">p. 259.</a></td> +<td align="left" valign="top">B.2. Wanting in France?</td> +</tr> + +<tr> +<td align="left" valign="top">B.2. Wanting in England?</td> +<td align="left" valign="top">B.2. Soissonnais Sands, or Lits +Coquilliers, <a href="page 275">p. 275</a></td> +</tr> + +<tr> +<td colspan="2" align="center"><small>LOWER EOCENE</small></td> +</tr> + +<tr> +<td align="left" valign="top">C.1. London Clay, <a href="page 263"> +p. 263.</a></td> +<td align="left" valign="top">C.1. Argile de Londres, Cassel, near +Dunkirk.</td> +</tr> + +<tr> +<td align="left" valign="top">C.2. Woolwich and Reading series, <a +href="page 267">p. 267.</a></td> +<td align="left" valign="top">C.2. Argile plastique and lignite, <a +href="page 276">p. 276</a></td> +</tr> + +<tr> +<td align="left" valign="top">C.3. Thanet sands, <a href= +"page 269">p. 269.</a></td> +<td align="left" valign="top">C.3. Sables de Bracheux, <a href= +"page 276">p. 276</a></td> +</tr> +</table> +</center> + +<br> + + +<center><small>UPPER EOCENE, ENGLAND.</small></center> + +<p><b>Bembridge Series, A.1.</b>—These beds are about 120 +feet thick, and, as stated in <a href="ch15.html#page 245">p. +245,</a> lie immediately under the Hempstead beds, near Yarmouth, +in the Isle of Wight, being conformable with those Lower Miocene +strata. They consist of marls, clays, and limestones of +fresh-water, brackish, and marine origin. Some of the most abundant +shells, as <i>Cyrena semistriata</i> var., and <i>Paludina +lenta,</i> <a href="../images1/fig158.jpg">Fig. 163,</a> are common to +this and to the overlying Hempstead series; but the majority of the +species are distinct. The following are the subdivisions described +by the late Professor Forbes:<br> + <i>a.</i> Upper marls, distinguished +by the abundance of <i>Melania turritissima,</i> Forbes (<a href= +"../images1/fig165.jpg">Fig. 165</a>).<br> + <i>b.</i> Lower marls, characterised +by <i>Cerithium mutabile, Cyrena pulchra,</i> etc., and by the +remains of <i>Trionyx</i> (see <a href="../images1/fig165.jpg">Fig. +166</a>).<br> + <i>c.</i> Green marls, often +abounding in a peculiar species of oyster, and accompanied by <i> +Cerithium, Mytilus, Arca, nucula,</i> etc.<br> + <i>d.</i> Bembridge limestones, +compact cream-coloured limestones alternating with shales and +marls, in all of which land-shells are common, especially at +Sconce, near Yarmouth,</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 253">[ 253 ]</a></p> + +<center><img src="../images1/fig165.jpg" width="418" height="584" alt= +"Fig. 165: Melania turritissima, Fig. 166: Fragment of Carapace of Trionyx, Fig. 167: Bulimus ellipticus, Fig. 168: Helix occlusa, Fig. 169: Paludina orbicularis, Fig. 170: Planorbis discus, Fig. 171: Lymnea longiscata, Fig. 172: Chara tuberculata."> +</center> + +<p>as described by Mr. F. Edwards. The <i>Bulimus ellipticus,</i> +Fig. 167, and <i>Helix occlusa,</i> Fig. 168, are among its best +known land-shells. <i>Paludina orbicularis,</i> Fig. 169, is also +of frequent occurrence. One of the bands is filled with a little +globular <i>Paludina.</i> Among the fresh-water pulmonifera, <i> +Lymnea longiscata</i> (Fig. 171) and <i>Planorbis discus</i> (Fig. +170)</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 254">[ 254 ]</a></p> + +<p>are the most generally distributed: the latter represents or +takes the place of the <i>Planorbis euomphalus</i> (see <a href= +"../images1/fig175.jpg">Fig. 175</a>) of the more ancient Headon +series. <i>Chara tuberculata</i> <a href="../images1/fig165.jpg">(Fig. +172)</a> is the characteristic Bembridge gyrogonite or +seed-vessel.</p> + +<img src="../images1/fig173.jpg" width="126" height="176" alt= +"Fig. 173: Lower molar tooth." align="right"> + +<p>From this formation on the shores of Whitecliff Bay, Dr. Mantell +obtained a fine specimen of a fan palm, <i>Flabellaria +Lamanonis,</i> Brong., a plant first obtained from beds of +corresponding age in the suburbs of Paris. The well-known +building-stone of Binstead, near Ryde, a limestone with numerous +hollows caused by Cyrenæ which have disappeared and left the +moulds of their shells, belongs to this subdivision of the +Bembridge series. In the same Binstead stone Mr. Pratt and the +Reverend Darwin Fox first discovered the remains of mammalia +characteristic of the gypseous series of Paris, as <i> +Palæotherium magnum</i> (Fig. 174), <i>P. medium, P. minus, +P. minimum, P. curtum, P. crassum</i>; also <i>Anoplotherium +commune</i> (Fig. 173), <i>A. secundarium, Dichobune cervinum,</i> +and <i>Chæropotamus Cuvieri.</i> The Palæothere above +alluded to resembled the living tapir in the form of the head, and +in having a short proboscis, but its molar teeth were more like +those of the rhinoceros. <i>Palæotherium magnum</i> was of +the size of a horse, three or four feet high. The woodcut, Fig. +174, is one of the restorations which Cuvier attempted of the +outline of the living animal, derived from the study of the entire +skeleton.</p> + +<center><img src="../images1/fig174.jpg" width="392" height="246" alt= +"Fig. 174: Palæotherium magnum."></center> + +<p> </p> + +<hr> +<p class="page"><a name="page 255">[ 255 ]</a></p> + +<p>As the vertical range of particular species of quadrupeds, so +far as our knowledge extends, is far more limited than that of the +testacea, the occurrence of so many species at Binstead, agreeing +with fossils of the Paris gypsum, strengthens the evidence derived +from shells and plants of the synchronism of the two +formations.</p> + +<p><b>Osborne or St. Helen’s Series, A.2.</b>—This +group is of fresh and brackish-water origin, and very variable in +mineral character and thickness. Near Ryde, it supplies a freestone +much used for building, and called by Professor Forbes the +Nettlestone grit. In one part ripple-marked flagstones occur, and +rocks with fucoidal markings. The Osborne beds are distinguished by +peculiar species of <i>Paludina, Melania,</i> and <i> +Melanopsis,</i> as also of <i>Cypris</i> and the seeds of <i> +Chara.</i></p> + +<center><img src="../images1/fig175.jpg" width="403" height="165" alt= +"Fig. 175: Planorbis euomphalus, Fig. 176: Helix labyrinthica."> +</center> + +<p><b>Headon Series A.3.</b>—These beds are seen both in +Whitecliff Bay, Headon Hill, and Alum Bay, or at the east and west +extremities of the Isle of Wight. The upper and lower portions are +fresh-water, and the middle of mixed origin, sometimes brackish and +marine. Everywhere <i>Planorbis euomphalus,</i> Fig. 175, +characterises the fresh-water deposits, just as the allied form, P. +discus, <a href="../images1/fig165.jpg">Fig. 170,</a> does the +Bembridge limestone. The brackish-water beds contain <i>Potamomya +plana, Cerithium mutabile,</i> and <i>Potamides cinctus</i> (<a +href="../images/fig37.jpg">Fig. 37</a>), and the marine beds <i> +Venus</i> (or <i>Cytherea</i>) <i>incrassata,</i> a species common +to the Limburg beds and Grès de Fontainebleau, or the Lower +Miocene series. The prevalence of salt-water remains is most +conspicuous in some of the central parts of the formation.</p> + +<img src="../images1/fig177.jpg" width="102" height="91" alt= +"Fig. 177: Neritina concava." align="right"> + +<p>Among the shells which are widely distributed through the Headon +series are <i>Neritina concava</i> (Fig. 177), <i>Lymnea +caudata</i> <a href="../images1/fig178.jpg">(Fig. 178),</a> and <i> +Cerithium concavum</i> <a href="../images1/fig178.jpg">(Fig. 179).</a> +<i>Helix labyrinthica,</i> Say (Fig. 176), a land-shell now +inhabiting the United States, was discovered in this series by Mr. +Searles Wood in Hordwell Cliff. It is also</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 256">[ 256 ]</a></p> + +<img src="../images1/fig178.jpg" width="136" height="339" alt= +"Fig. 178: Lymnea caudata, Fig. 179: Cerithium concavum." align= +"left"> + +<p>met with in Headon Hill, in the same beds. At Sconce, in the +Isle of Wight, it occurs in the Bembridge series, and affords a +rare example of an Eocene fossil of a species still living, though, +as usual in such cases, having no local connection with the actual +geographical range of the species. The lower and middle portion of +the Headon series is also met with in Hordwell Cliff (or Hordle, as +it is often spelt), near Lymington, Hants. Among the shells which +abound in this cliff are <i>Paludina lenta</i> and various species +of <i>Lymnea, Planorbis, Melania, Cyclas, Unio, Potamomya, +Dreissena,</i> etc.</p> + +<p>Among the chelonians we find a species of <i>Emys,</i> and no +less than six species of <i>Trionyx</i>; among the saurians an +alligator and a crocodile; among the ophidians two species of +land-snakes (<i>Paleryx,</i> Owen); and among the fish Sir P. +Egerton and Mr. Wood have found the jaws, teeth, and hard shining +scales of the genus <i>Lepidosteus,</i> or bony pike of the +American rivers. This same genus of fresh-water ganoids has also +been met with in the Hempstead beds in the Isle of Wight. The bones +of several birds have been obtained from Hordwell, and the remains +of quadrupeds of the genera <i>Palæotherium (P. minus), +Anoplotherium, Anthracotherium, Dichodon, Dichobune, +Spalacodon,</i> and <i>Hyænodon.</i> The latter offers, I +believe, the oldest known example of a true carnivorous animal in +the series of British fossils, although I attach very little +theoretical importance to the fact, because herbivorous species are +those most easily met with in a fossil state in all save cavern +deposits. In another point of view, however, this fauna deserves +notice. Its geological position is considerably lower than that of +the Bembridge or Montmartre beds, from which it differs almost as +much in species as it does from the still more ancient fauna of the +Lower Eocene beds to be mentioned in the sequel. It therefore +teaches us what a grand succession of distinct assemblages of +mammalia flourished on the earth during the Eocene period.</p> + +<p>Many of the marine shells of the brackish-water beds of the +above series, both in the Isle of Wight and Hordwell Cliff, are +common to the underlying Barton Clay: and, on the other hand, there +are some fresh-water shells, such as <i>Cyrena obovata,</i> which +are common to the Bembridge beds, not-</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 257">[ 257 ]</a></p> + +<p>withstanding the intervention of the St. Helen’s series. +The white and green marls of the Headon series, and some of the +accompanying limestones, often resemble the Eocene strata of France +in mineral character and colour in so striking a manner as to +suggest the idea that the sediment was derived from the same region +or produced contemporaneously under very similar geographical +circumstances.</p> + +<p>At Brockenhurst, near Lyndhurst, in the New Forest, marine +strata have recently been found containing fifty-nine shells, of +which many have been described by Mr. Edwards. These beds rest on +the Lower Headon, and are considered as the equivalent of the +middle part of the Headon series, many of the shells being common +to the brackish-water or Middle Headon beds of Colwell and +Whitecliff Bays, such as <i>Cancellaria muricata,</i> Sowerby, <i> +Fusus labiatus,</i> Sowerby, etc. In these beds at Brockenhurst, +corals, ably described by Dr. Duncan, have recently been found in +abundance and perfection; see Fig. 180, <i>Solenastræa +cellulosa.</i></p> + +<img src="../images1/fig180.jpg" width="179" height="194" alt= +"Fig. 180: Solenastræa cellulosa." align="right"> + +<p>Baron von Könen* has pointed out that no less than +forty-six out of the fifty-nine Brockenhurst shells, or a +proportion of 78 per cent, agree with species occurring in +Dumont’s Lower Tongrian formation in Belgium. This being the +case, we might fairly expect that if we had a marine equivalent of +the Bembridge series or of the contemporaneous Paris gypsum, we +should find it to contain a still greater number of shells common +to the Tongrian beds of Belgium, but the exact correlation of these +fresh-water groups of France, Belgium, and Britain has not yet been +fully made out. It is possible that the Tongrian of Dumont may be +newer than the Bembridge series, and therefore referable to the +Lower Miocene. If ever the whole series should be complete, we must +be prepared to find the marine equivalent of the Bembridge beds, or +the uppermost Eocene, passing by imperceptible shades into the +inferior beds of the overlying Miocene strata.</p> + +<p>Among the fossils found in the Middle Headon are <i>Cytherea +incrassata</i> and <i>Cerithium plicatum</i> <a href= +"../images1/fig158.jpg">(Fig. 160).</a> These shells, especially the +latter, are very characteristic of the Lower Miocene, and their +occurrence in the Headon series has been cited as an objection to +the line proposed to be</p> + +<p class="fnote">* Quart. Geol. Journal, vol. xx, p. 97, 1864.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 258">[ 258 ]</a></p> + +<p>drawn between Miocene and Eocene. But if we were to attach +importance to such occasional passages, we should soon find that no +lines of division could be drawn anywhere, for in the present state +of our knowledge of the Tertiary series there will always be +species common to beds above and below our boundary-lines.</p> + +<img src="../images1/fig181.jpg" width="99" height="142" alt= +"Fig. 181: Chama squamosa." align="left"> + +<p><b>Barton Series</b> (<i>Sands and Clays</i>), <b>A.4</b> <a +href="#page 252">Table</a>—Both in the Isle of Wight, and in +Hordwell Cliff, Hants, the Headon beds, above-mentioned, rest on +white sands usually devoid of fossils, and used in the Isle of +Wight for making glass. In one of these sands Dr. Wright found <i> +Chama squamosa,</i> a Barton Clay shell, in great plenty, and +certain impressions of marine shells have been found in sands +supposed to be of the same age in Whitecliff Bay. These sands have +been called Upper Bagshot in the maps of our Government Survey, but +this identification of a fossiliferous series in the Isle of Wight +with an unfossiliferous formation in the London Basin can scarcely +be depended upon. The Barton Clay, which immediately underlies +these sands, is seen vertical in Alum Bay, Isle of Wight, and +nearly horizontal in the cliffs of the mainland near Lymington. +This clay, together with the Bracklesham beds, presently to be +described, has been termed Middle Bagshot by the Survey. In Barton +Cliff, where it attains a thickness of about 300 feet, it is rich +in marine fossils.</p> + +<p>It was formerly confounded with the London Clay, an older Eocene +deposit of very similar mineral character, to be mentioned (<a +href="#page 263">p. 263</a>), which contains many shells in common, +but not more than one-fourth of the whole. In other words, there +are known at present 247 species in the London Clay and 321 in that +of Barton, and only 70 common to the two formations. Fifty-six of +these have been found in the intermediate Bracklesham beds, and the +reappearance of the other 14 may imply a return of similar +conditions, whether of temperature or depth or of a muddy +argillaceous bottom, common to the two periods of the London and +Barton Clays. According to M. Hebert, the most characteristic +Barton Clay fossils correspond to those of the Gres de Beauchamp, +or Sables Moyens, of the Paris Basin, but it also contains many +common to the older Calcaire Grossier.</p> + +<br> +<br> + + +<center><small>SHELLS OF THE BARTON CLAY.</small></center> + +<p>Certain foraminifera called Nummulites begin, when we study the +Tertiary formations in a descending order, to make</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 259">[ 259 ]</a></p> + +<p>their first appearance in these beds. A small species called <i> +Nummulites variolaria,</i> Fig. 190, is found both on the Hampshire +coast and in beds of the same age in Whitecliff Bay, in the Isle of +Wight. Several marine shells, such as <i>Corbula pisum</i> <a href= +"../images1/fig158.jpg">(Fig. 158),</a> are common to the Barton beds +and the Hempstead or Lower Miocene series, and a still greater +number, as before stated, are common to the Headon series.</p> + +<center><img src="../images1/fig182.jpg" width="371" height="503" alt= +"Fig. 182: Mitra scabra, Fig. 183: Voluta ambigua, Fig. 184: Typhis pungens, Fig. 185: Voluta athleta, Fig. 186: Terebellum fusiforme, Fig. 187: Terebellum sopita, Fig. 188: Cardita sulcata, Fig. 189: Crassatella sulcata, Fig. 190: Nummulites variolaria."> +</center> + +<br> +<br> +<center><small>MIDDLE EOCENE, ENGLAND.</small></center> + +<p><b>Bracklesham Beds and Bagshot Sands, B.1,</b> <a href= +"#page 252">Table</a>—Beneath the Barton Clay we find in the +north of the Isle of Wight, both in Alum and Whitecliff Bays, a +great series of various coloured sands and clays for the most part +unfossiliferous,</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 260">[ 260 ]</a></p> + +<p>and probably of estuarine origin. As some of these beds contain +<i>Cardita planicosta</i> (Fig. 191) they have been identified with +the marine beds much richer in fossils seen in the coast section in +Bracklesham Bay near Chichester in Sussex, where the strata consist +chiefly of green clayey sands with some lignite. Among the +Bracklesham fossils besides the Cardita, the huge <i>Cerithium +giganteum</i> is seen, so conspicuous in the Calcaire Grossier of +Paris, where it is sometimes two feet in length. The <i>Nummulites +lævigata</i> (see Fig. 192), so characteristic of the lower +beds of the Calcaire Grossier in France, where it sometimes forms +stony layers, as near Compiègne, is very common in these +beds, together with <i>N. scabra</i> and <i>N. variolaria.</i> Out +of 193 species of testacea procured from the Bagshot and +Bracklesham beds in England, 126 occur in the Calcaire Grossier in +France. It was clearly, therefore, coeval with that part of the +Parisian series more nearly than with any other.</p> + +<center><img src="../images1/fig191.jpg" width="318" height="401" alt= +"Fig. 191: Cardita (Venericardia) planicosta, Fig. 192: Nummulites (Nummularia) lavigata."> +</center> + +<p>According to tables compiled from the best authorities by Mr. +Etheridge, the number of mollusca now known from the Bracklesham +beds in Great Britain is 393, of which no less</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 261">[ 261 ]</a></p> + +<center><img src="../images1/fig193.jpg" width="411" height="286" alt= +"Fig. 193: Palæophis typhoeus, Owen; an Eocene sea-serpent, Fig. 194: Defensive spine of Ostracion."> +</center> + +<img src="../images1/fig195.jpg" width="195" height="177" alt= +"Fig. 195: Dental plates of Myliobates Edwardsi." align="right"> + +<p>than 240 are peculiar to this subdivision of the British Eocene +series, while 70 are common to the Older London Clay, and 140 to +the Newer Barton Clay. The volutes and cowries of this formation, +as well as the lunulites and corals, favour the idea of a warm +climate having prevailed, which is borne out by the discovery of a +serpent, <i>Palæophis typhœus</i> (see Fig. 193), +exceeding, according to Professor Owen, twenty feet in length, and +allied in its osteology to the Boa, Python, Coluber, and Hydrus. +The compressed form and diminutive size of certain caudal +vertebræ indicate so much analogy with Hydrus as to induce +Professor Owen to pronounce this extinct ophidian to have been +marine.* Among the companions of the sea-snake of Bracklesham was +an extinct crocodile (<i>Gavialis Dixoni,</i> Owen), and numerous +fish, such as now frequent the seas of warm latitudes, as the +Ostracion of the family Balistidæ, of which a dorsal spine is +figured (see Fig. 194), and gigantic rays of the genus <i> +Myliobates</i> (see Fig. 195).</p> + +<p>The teeth of sharks also, of the genera <i>Carcharodon, Otodus, +Lamna, Galeocerdo,</i> and others, are abundant. (See Figs. 196, +197, 198, 199.)</p> + +<p class="fnote">* Palæont. Soc. Monograph, Rept., pt. ii, p. +61.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 262">[ 262 ]</a></p> + +<center><img src="../images1/fig196.jpg" width="406" height="256" alt= +"Fig. 196: Carcharodon angustidens, Fig. 197: Otodus obliquus, Fig. 198: Lamna elegans, Fig. 199: Galcocerdo latidens."> +</center> + +<br> +<br> + + +<center><small>MARINE SHELLS OF BRACKLESHAM BEDS.</small></center> + +<p><b>Alum Bay and Bournemouth Beds.</b> (<i>Lower Bagshot of +English Survey</i>), <b>B.2,</b> <a href="#page 252"> +Table</a>—To that great series of sands and clays which +intervene between the equivalents of the Bracklesham Beds and the +London Clay or Lower Eocene, our Government Survey has given the +name of the Lower Bagshot sands, for they are supposed to agree in +age with the inferior unfossiliferous sands of the country round +Bagshot in the London Basin. This part of the series is finely +exposed in the vertical beds of Alum bay, in the Isle of Wight, and +east and west of Bournemouth, on the south coast of Hampshire. In +some of the close and white compact clays of this locality, there +are not only dicotyledonous leaves, but numerous fronds of ferns +allied to Gleichenia which are well preserved with their fruit.</p> + +<center><img src="../images1/fig200.jpg" width="411" height="185" alt= +"Fig. 200: Pleurotoma attenuata, Fig. 201: Voluta Selseïensis, Fig. 202: Turritella multisulcata, Fig. 203: Lucina serrata, Fig. 204: Conus deperditus."> +</center> + +None of the beds are of great horizontal extent, and there is much +cross-stratification in the sands, and in some places<br> +<br> + + +<p> </p> + +<hr> +<p class="page"><a name="page 263">[ 263 ]</a></p> + +<p>black carbonaceous seams and lignite. In the midst of these +leaf-beds in Studland Bay, Purbeck shells of the genus Unio attest +the fresh-water origin of the white clay.</p> + +<p>No less than forty species of plants are mentioned by MM. de la +Harpe and Gaudin from this formation in Hampshire, among which the +Proteaceæ (<i>Dryandra,</i> etc.) and the fig tribe are +abundant, as well as the cinnamon and several other laurineæ, +with some papilionaceous plants. On the whole, they remind the +botanist of the types of subtropical India and Australia.*</p> + +<p>Heer has mentioned several species which are common to this Alum +Bay flora and that of Monte Bolca, near Verona, so celebrated for +its fossil fish, and where the strata contain nummulites and other +Middle Eocene fossils. He has particularly alluded to <i>Aralia +primigenia</i> (of which genus a fruit has since been found by Mr. +Mitchell at Bournemouth), <i>Daphnogene Veronensis,</i> and <i> +Ficus granadilla,</i> as among the species common to and +characteristic of the Isle of Wight and Italian Eocene beds; and he +observes that in the flora of this period these forms of a +temperate climate which constitute a marked feature in the European +Miocene formations, such as the willow, poplar, birch, alder, elm, +hornbeam, oak, fir, and pine, are wanting. The American types are +also absent, or much more feebly represented than in the Miocene +period, although fine specimens of the fan-palm (<i>Sabal</i>) have +been found in these Eocene clays at Studland. The number of exotic +forms which are common to the Eocene and Miocene strata of Europe, +like those to be alluded to in the sequel which are common to the +Eocene and Cretaceous fauna, demonstrate the remoteness of the +times in which the geographical distribution of living plants +originated. A great majority of the Eocene genera have disappeared +from our temperate climates, but not the whole of them; and they +must all have exerted some influence on the assemblages of species +which succeeded them. Many of these last occurring in the Upper +Miocene are indeed so closely allied to the flora now surviving as +to make it questionable, even in the opinion of naturalists opposed +to the doctrine of transmutation, whether they are not +genealogically related the one to the other.</p> + +<br> + + +<center><small>LOWER EOCENE FORMATIONS, ENGLAND.</small></center> + +<p>London Clay, C.1, <a href="#page 252">Table</a>—This +formation underlies the preceding, and sometimes attains a +thickness of 500 feet. It consists of tenacious brown and +bluish-grey clay,</p> + +<p class="fnote">* Heer, Climat et Végétation du Pays +Tertiaire, p. 172.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 264">[ 264 ]</a></p> + +<p>with layers of concretions called septaria, which abound chiefly +in the brown clay, and are obtained in sufficient numbers from +sea-cliffs near Harwich, and from shoals off the coast of Essex and +the Isle of Sheppey, to be used for making Roman cement. The total +number of British fossil mollusca known at present (January, 1870) +in this formation are 254, of which 166 are peculiar, or not found +in other Eocene beds in this country. The principal localities of +fossils in the London clay are Highgate Hill, near London, the +Island of Sheppey at the mouth of the Thames, and Bognor on the +Sussex coast. Out of 133 fossil shells, Mr. Prestwich found only 20 +to be common to the Calcaire Grossier (from which 600 species have +been obtained), while 33 are common to the “Lits +Coquilliers” (<a href="#page 275">p. 275</a>), in which 200 +species are known in France.</p> + +<p>In the Island of Sheppey near the mouth of the Thames, the +thickness of the London Clay is estimated by Mr. Prestwich to be +more than 500 feet, and it is in the uppermost 50 feet that a great +number of fossil fruits were obtained, being chiefly found on the +beach when the sea has washed away the clay of the rapidly wasting +cliffs.</p> + +<img src="../images1/fig205.jpg" width="168" height="219" alt= +"Fig. 205: Nipadites ellipticus." align="left"> + +<p>Mr. Bowerbank, in a valuable publication on these fossil fruits +and seeds, has described no less than thirteen fruits of palms of +the recent type <i>Nipa,</i> now only found in the Molucca and +Philippine Islands, and in Bengal (see Fig. 205). In the delta of +the Ganges, Dr. Hooker observed the large nuts of <i>Nipa +fruticans</i> floating in such numbers in the various arms of that +great river, as to obstruct the paddle-wheels of steamboats. These +plants are allied to the cocoanut tribe on the one side, and on the +other to the <i>Pandanus,</i> or screw-pine. There are also met +with three species of <i>Anona,</i> or custard-apple; and +cucurbitaceous fruits (of the gourd and melon family), and fruits +of various species of <i>Acacia.</i></p> + +<p>Besides fir-cones or fruit of true Coniferæ there are +cones of Proteaceæ in abundance, and the celebrated botanist +the late Robert Brown pointed out the affinity of these to the New +Holland types <i>Petrophila</i> and <i>Isopogon.</i> Of the first +there are about fifty, and of the second thirty described species +now living in Australia.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 265">[ 265 ]</a></p> + +<img src="../images1/fig206.jpg" width="182" height="228" alt= +"Fig. 206: Eocene Proteaceous Fruit (Petrophiloides Richardsoni." +align="right"> + +<p>Ettingshausen remarked in 1851 that five of the fossil species +from Sheppey, named by Bowerbank* were specimens of the same fruit +(see Fig. 206), in different states of preservation; and Mr. +Carruthers, having examined the original specimens now in the +British Museum, tells me that all these cones from Sheppey may be +reduced to two species, which have an undoubted affinity to the two +existing Australian genera above mentioned, although their perfect +identity in structure can not be made out.</p> + +<p>The contiguity of land may be inferred not only from these +vegetable productions, but also from the teeth and bones of +crocodiles and turtles, since these creatures, as Dean Conybeare +remarked, must have resorted to some shore to lay their eggs. Of +turtles there were numerous species referred to extinct genera. +These are, for the most part, not equal in size to the largest +living tropical turtles. A sea-snake, which must have been thirteen +feet long, of the genus <i>Palæophis</i> before mentioned (p. +261) has also been described by Professor Owen from Sheppey, of a +different species from that of Bracklesham, and called <i>P. +toliapicus.</i> A true crocodile, also, <i>Crocodilus +toliapicus,</i> and another saurian more nearly allied to the +gavial, accompany the above fossils; also the relics of several +birds and quadrupeds. One of these last belongs to the new genus +<i>Hyracotherium</i> of Owen, of the hog tribe, allied to +Chæropotamus, another is a <i>Lophiodon</i>; a third a +pachyderm called <i>Coryphodon eocænus</i> by Owen, larger +than any existing tapir. All these animals seem to have inhabited +the banks of the great river which floated down the Sheppey fruits. +They imply the existence of a mammiferous fauna antecedent to the +period when nummulites flourished in Europe and Asia, and therefore +before the Alps, Pyrenees, and other mountain-chains now forming +the backbones of great continents, were raised from the deep; nay, +even before a part of the constituent rocky masses now entering +into the central ridges of these chains had been deposited in the +sea.</p> + +<p>The marine shells of the London Clay confirm the inference +derivable from the plants and reptiles in favour of a high +temperature. Thus many species of <i>Conus</i> and <i> +Voluta</i></p> + +<p class="fnote">* Bowerbank, Fossil Fruits and Seeds of London +Clay, Plates ix and x.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 266">[ 266 ]</a></p> + +<p>occur, a large <i>Cypræa, C. oviformis,</i> a very large +<i>Rostellaria</i> (Fig. 209), a species of <i>Cancellaria,</i> six +species of <i>Nautilus</i> (Fig. 211), besides other Cephalopoda of +extinct genera, one of the most remarkable of which is the <i> +Belosepia</i> (Fig. 212).</p> + +<center><img src="../images1/fig207.jpg" width="419" height="632" alt= +"Fig. 207: Voluta nodosa, Fig. 208: Phorus extensus, Fig. 209: Rostellaria (Hippocrenes) ampla, Fig. 210: Nautilus centralis, Fig. 211: Aturia ziczac, Fig. 212: Belosepia sepioidea, Fig. 213: Leda amygdaloides, Fig. 214: Cyptodon (Axinus) angulatum, Fig. 215: Astropecten crispatus."> +</center> + +<p> </p> + +<hr> +<p class="page"><a name="page 267">[ 267 ]</a></p> + +<p>Among many characteristic bivalve shells are <i>Leda +amygdaloides</i> (Fig. 213) and <i>Cryptodon angulatum</i> (Fig. +214), and among the Radiata a star-fish, <i>Astropecten</i> (Fig. +215.)</p> + +<p>These fossils are accompanied by a sword-fish (<i>Tetrapterus +priscus,</i> Agassiz), about eight feet long, and a saw-fish +(<i>Pristis bisulcatus,</i> Agassiz), about ten feet in length; +genera now foreign to the British seas. On the whole, about eighty +species of fish have been described by M. Agassiz from these beds +of Sheppey, and they indicate, in his opinion, a warm climate.</p> + +<p>In the lower part of the London clay at Kyson, a few miles east +of Woodbridge, the remains of mammalia have been detected. Some of +these have been referred by Professor Owen to an opossum, and +others to the genus <i>Hyracotherium.</i> The teeth of this +last-mentioned pachyderm were at first, in 1840, supposed to belong +to a monkey, an opinion afterwards abandoned by Owen when more +ample materials for comparison were obtained.</p> + +<p><b>Woolwich and Reading Series, C.2,</b> <a href="#page 252"> +Table</a>—This formation was formerly called the Plastic +Clay, as it agrees with a similar clay used in pottery which +occupies the same position in the French series, and it has been +used for the like purposes in England.*</p> + +<p>No formations can be more dissimilar, on the whole, in mineral +character than the Eocene deposits of England and Paris; those of +our own island being almost exclusively of mechanical +origin—accumulations of mud, sand, and pebbles; while in the +neighbourhood of Paris we find a great succession of strata +composed of limestones, some of them siliceous, and of crystalline +gypsum and siliceous sandstone, and sometimes of pure flint used +for millstones. Hence it is often impossible, as before stated, to +institute an exact comparison between the various members of the +English and French series, and to settle their respective ages. But +in regard to the division which we have now under consideration, +whether we study it in the basins of London, Hampshire, or Paris, +we recognise as a general rule the same mineral character, the beds +consisting over a large area of mottled clays and sand, with +lignite, and with some strata of well-rolled flint pebbles, derived +from the chalk, varying in size, but occasionally several inches in +diameter. These strata may be seen in the Isle of Wight in contact +with the chalk, or in the London basin, at Reading, Blackheath, and +Woolwich. In some of the lowest of them, banks of oysters are +observed, consisting of <i>Ostrea bellovacina,</i> so common in +France in the</p> + +<p class="fnote">* Prestwich, Quart. Geol. Journ., vol. x.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 268">[ 268 ]</a></p> + +<p>same relative position. In these beds at Bromley, Dr. Buckland +found a large pebble to which five full-grown oysters were affixed, +in such a manner as to show that they had commenced their first +growth upon it, and remained attached to it through life.</p> + +<center><img src="../images1/fig216.jpg" width="382" height="238" alt= +"Fig. 216: Cyrena cuneiformis, Fig. 217: Melania (Melanatria) inquinata."> +</center> + +<p>In several places, as at Woolwich on the Thames, at Newhaven in +Sussex, and elsewhere, a mixture of marine and fresh-water testacea +distinguishes this member of the series. Among the latter, <i> +Cyrena cuneiformis</i> (see Fig. 216) and <i>Melania inquinata</i> +(see Fig. 217) are very common, as in beds of corresponding age in +France. They clearly indicate points where rivers entered the +Eocene sea. Usually there is a mixture of brackish, fresh-water, +and marine shells, and sometimes, as at Woolwich, proofs of the +river and the sea having successively prevailed on the same spot. +At New Charlton, in the suburbs of Woolwich, Mr. de la Condamine +discovered in 1849, and pointed out to me, a layer of sand +associated with well-rounded flint pebbles in which numerous +individuals of the <i>Cyrena tellinella</i> were seen standing +endwise with both their valves united, the siphonal extremity of +each shell being uppermost, as would happen if the mollusks had +died in their natural position. I have described a bank of +sandy mud, in the delta of the Alabama River at Mobile, on the +borders of the Gulf of Mexico, where in 1846 I dug out at low tide +specimens of living species of <i>Cyrena</i> and of a <i> +Gnathodon,</i> which were similarly placed with their shells erect, +or in a posture which enables the animal to protrude its siphon +upward, and draw in or reject water at pleasure. The water at +Mobile is usually fresh,</p> + +<p class="fnote">* Second Visit to the United States, vol. ii, p. +104.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 269">[ 269 ]</a></p> + +<p>but sometimes brackish. At Woolwich a body of river-water must +have flowed permanently into the sea where the <i>Cyrenæ</i> +lived, and they may have been killed suddenly by an influx of pure +salt-water, which invaded the spot when the river was low, or when +a subsidence of land took place. Traced in one direction, or +eastward towards Herne Bay, the Woolwich beds assume more and more +of a marine character; while in an opposite, or south-western +direction, they become, as near Chelsea and other places, more +fresh-water, and contain <i>Unio, Paludina,</i> and layers of +lignite, so that the land drained by the ancient river seems +clearly to have been to the south-west of the present site of the +metropolis.</p> + +<p><i>Fluviatile Beds underlying Deep-sea Strata.</i>—Before +the minds of geologists had become familiar with the theory of the +gradual sinking of land, and its conversion into sea at different +periods, and the consequent change from shallow to deep water, the +fluviatile and littoral character of this inferior group appeared +strange and anomalous. After passing through hundreds of feet of +London clay, proved by its fossils to have been deposited in deep +salt-water, we arrive at beds of fluviatile origin, and associated +with them masses of shingle, attaining at Blackheath, near London, +a thickness of 50 feet. These shingle banks are probably of marine +origin, but they indicate the proximity of land, and the existence +of a shore where the flints of the chalk were rolled into sand and +pebbles, and spread over a wide space. We have, therefore, first, +as before stated (p. 268), evidence of oscillations of level during +the accumulation of the Woolwich series, then of a great +submergence, which allowed a marine deposit 500 thick to be laid +over the antecedent beds of fresh and brackish water origin.</p> + +<p><b>Thanet Sands, C.3,</b> <a href="#page 252"> +Table</a>—The Woolwich or plastic clay above described may +often be seen in the Hampshire basin in actual contact with the +chalk, constituting in such places the lowest member of the British +Eocene series. But at other points another formation of marine +origin, characterised by a somewhat different assemblage of organic +remains, has been shown by Mr. Prestwich to intervene between the +chalk and the Woolwich series. For these beds he has proposed the +name of “Thanet Sands,” because they are well seen in +the Isle of Thanet, in the northern part of Kent, and on the +sea-coast between Herne Bay and the Reculvers, where they consist +of sands with a few concretionary masses of sandstone, and contain, +among other fossils, <i>Pholadomya cuneata, Cyprina morrisii, +Corbula longirostris, Scalaria Bowerbankii,</i> etc. The greatest +thickness of these beds is 90 feet.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 270">[ 270 ]</a></p> + +<center><small>UPPER EOCENE FORMATIONS OF FRANCE.</small></center> + +<p>The tertiary formations in the neighbourhood of Paris consist of +a series of marine and fresh-water strata, alternating with each +other, and filling up a depression in the chalk. The area which +they occupy has been called the Paris Basin, and is about 180 miles +in its greatest length from north to south, and about 90 miles in +breadth from east to west. MM. Cuvier and Brongniart attempted, in +1810, to distinguish five different groups, comprising three +fresh-water and two marine, which were supposed to imply that the +waters of the ocean, and of rivers and lakes, had been by turns +admitted into and excluded from the same area. Investigations since +made in the Hampshire and London basins have rather tended to +confirm these views, at least so far as to show that since the +commencement of the Eocene period there have been great movements +of the bed of the sea, and of the adjoining lands, and that the +superposition of deep-sea to shallow-water deposits (the London +Clay, for example, to the Woolwich beds) can only be explained by +referring to such movements. It appears, notwithstanding, from the +researches of M. Constant Prevost, that some of the minor +alternations and intermixtures of fresh-water and marine deposits, +in the Paris basin, may be accounted for without such changes of +level, by imagining both to have been simultaneously in progress, +in the same bay of the same sea, or a gulf into which many rivers +entered.</p> + +<p><b>Gypseous Series of Montmartre, A.1,</b> <a href="#page 252"> +Table</a>—To enlarge on the numerous subdivisions of the +Parisian strata would lead me beyond my present limits; I shall +therefore give some examples only of the most important formations. +Beneath the Grès de Fontainebleau, belonging to the Lower +Miocene period, as before stated, we find, in the neighbourhood of +Paris, a series of white and green marls, with subordinate beds of +gypsum. These are most largely developed in the central parts of +the Paris basin, and, among other places, in the hill of +Montmartre, where its fossils were first studied by Cuvier.</p> + +<p>The gypsum quarried there for the manufacture of plaster of +Paris occurs as a granular crystalline rock, and, together with the +associated marls, contains land and fluviatile shells, together +with the bones and skeletons of birds and quadrupeds. Several +land-plants are also met with, among which are fine specimens of +the fan-palm or palmetto tribe (<i>Flabellaria</i>). The remains +also of fresh-water fish, and of crocodiles and other reptiles, +occur in the gypsum. The skeletons of</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 271">[ 271 ]</a></p> + +<p>mammalia are usually isolated, often entire, the most delicate +extremities being preserved; as if the carcasses, clothed with +their flesh and skin, had been floated down soon after death, and +while they were still swollen by the gases generated by their first +decomposition. The few accompanying shells are of those light kinds +which frequently float on the surface of rivers, together with +wood.</p> + +<p>In this formation the relics of about fifty species of +quadrupeds, including the genera <i>Palæotherium</i> (see <a +href="../images1/fig174.jpg">Fig. 174</a>), <i>Anoplotherium</i> (see +Fig. 218), and others, have been found, all extinct, and nearly +four-fifths of them belonging to the Perissodactyle or odd-toed +division of the order <i>Pachydermata,</i> which now contains only +four living genera, namely, rhinoceros, tapir, horse, and hyrax. +With them a few carnivorous animals are associated, among which are +the <i>Hyænodon dasyuroides,</i> a species of dog, <i>Canis +Parisiensis,</i> and a weasel, <i>Cynodon Parisiensis.</i> Of the +<i>Rodentia</i> are found a squirrel; of the <i>Cheiroptera,</i> a +bat; while the <i>Marsupalia</i> (an order now confined to America, +Australia, and some contiguous islands) are represented by an +opossum.</p> + +<p>Of birds, about ten species have been ascertained, the skeletons +of some of which are entire. None of them are referable to existing +species.* The same remark, according to MM. Cuvier and Agassiz, +applies both to the reptiles and fish. Among the last are +crocodiles and tortoises of the genera <i>Emys</i> and <i> +Trionyx.</i></p> + +<p><img src="../images1/fig218.jpg" width="256" height="237" alt= +"Fig. 218: Xiphodon gracile, or Anoplotherium gracile." align= +"right"></p> + +<p>The tribe of land quadrupeds most abundant in this formation is +such as now inhabits alluvial plains and marshes, and the banks of +rivers and lakes, a class most exposed to suffer by river +inundations. Among these were several species of <i> +Palæotherium,</i> a genus before alluded to. These were +associated with the Anoplotherium, a tribe intermediate between +pachyderms and ruminants. One of the three divisions of this family +was called by Cuvier <i>Xiphodon.</i> Their forms were slender +and</p> + +<p class="fnote">* Cuvier, Oss. Foss., tome iii, p. 255.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 272">[ 272 ]</a></p> + +<p>elegant, and one, named <i>Xiphodon gracile</i> (Fig. 218), was +about the size of the chamois; and Cuvier inferred from the +skeleton that it was as light, graceful, and agile as the +gazelle.</p> + +<p><i>Fossil Footprints.</i>—There are three superimposed +masses of gypsum in the neighbourhood of Paris, separated by +intervening deposits of laminated marl. In the uppermost of the +three, in the valley of Montmorency, M. Desnoyers discovered in +1859 many footprints of animals occurring at no less than six +different levels.* The gypsum to which they belong varies from +thirty to fifty feet in thickness, and is that which has yielded to +the naturalist the largest number of bones and skeletons of +mammalia, birds, and reptiles. I visited the quarries, soon after +the discovery was made known, with M. Desnoyers, who also showed me +large slabs in the Museum at Paris, where, on the upper planes of +stratification, the indented foot-marks were seen, while +corresponding casts in relief appeared on the lower surfaces of the +strata of gypsum which were immediately superimposed. A thin film +of marl, which before it was dried and condensed by pressure must +have represented a much thicker layer of soft mud, intervened +between the beds of solid gypsum. On this mud the animals had +trodden, and made impressions which had penetrated to the gypseous +mass below, then evidently unconsolidated. Tracks of the <i> +Anoplotherium</i> with its bisulcate hoof, and the trilobed +footprints of <i>Palæotherium,</i> were seen of different +sizes, corresponding to those of several species of these genera +which Cuvier had reconstructed, while in the same beds were +foot-marks of carnivorous mammalia. The tracks also of fluviatile, +lacustrine, and terrestrial tortoises (<i>Emys, Trionyx,</i> etc.) +were discovered, also those of crocodiles, iguanas, geckos, and +great batrachians, and the footprints of a huge bird, apparently a +wader, of the size of the gastornis, to be mentioned in the sequel. +There were likewise the impressions of the feet of other creatures, +some of them clearly distinguishable from any of the fifty extinct +types of mammalia of which the bones have been found in the Paris +gypsum. The whole assemblage, says Desnoyers, indicate the shores +of a lake, or several small lakes communicating with each other, on +the borders of which many species of pachyderms wandered, and +beasts of prey which occasionally devoured them. The tooth-marks of +these last had been detected by palæontologists long before +on the bones and skulls of Paleotheres entombed in the gypsum.</p> + +<p class="fnote">* Sur des Empreintes de Pas d’Animaux par M. +J. Desnoyers. Compte rendu de l’Institut, 1859.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 273">[ 273 ]</a></p> + +<p><i>Imperfection of the Record.</i>—These foot-marks have +revealed to us new and unexpected proofs that the air-breathing +fauna of the Upper Eocene period in Europe far surpassed in the +number and variety of its species the largest estimate which had +previously been formed of it. We may now feel sure that the +mammalia, reptiles, and birds which have left portions of their +skeletons as memorials of their existence in the solid gypsum +constituted but a part of the then living creation. Similar +inferences may be drawn from the study of the whole succession of +geological records. In each district the monuments of periods +embracing thousands, and probably in some instances hundreds of +thousands of years, are totally wanting. Even in the volumes which +are extant the greater number of the pages are missing in any given +region, and where they are found they contain but few and casual +entries of the physical events or living beings of the times to +which they relate. It may also be remarked that the subordinate +formations met with in two neighbouring countries, such as France +and England (the minor Tertiary groups above enumerated), commonly +classed as equivalents and referred to corresponding periods, may +nevertheless have been by no means strictly coincident in date. +Though called contemporaneous, it is probable that they were often +separated by intervals of many thousands of years. We may compare +them to double stars, which appear single to the naked eye because +seen from a vast distance in space, and which really belong to one +and the same stellar system, though occupying places in space +extremely remote if estimated by our ordinary standard of +terrestrial measurements.</p> + +<p><b>Calcaire silicieux, or Travertin inférieur, A.2 and +3,</b> <a href="#page 252">Table</a>—This compact siliceous +limestone extends over a wide area. It resembles a precipitate from +the waters of mineral springs, and is often traversed by small +empty sinuous cavities. It is, for the most part, devoid of organic +remains, but in some places contains fresh-water and land species, +and never any marine fossils. The calcaire siliceux and the +calcaire grossier usually occupy distinct parts of the Paris basin, +the one attaining its fullest development in those places where the +other is of slight thickness. They are described by some writers as +alternating with each other towards the centre of the basin, as at +Sergy and Osny.</p> + +<p>The gypsum, with its associated marls before described, is in +greatest force towards the centre of the basin, where the calcaire +grossier and calcaire silicieux are less fully developed.</p> + +<p><b>Grès de Beauchamp, or Sables Moyens, A.4,</b> <a href= +"#page 252">Table</a>—In some parts of the Paris basin, sands +and marls, called the</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 274">[ 274 ]</a></p> + +<p>Grès de Beauchamp, or Sables moyens, divide the gypseous +beds from the calcaire grossier proper. These sands, in which a +small nummulite (N. variolaria) is very abundant, contain more than +300 species of marine shells, many of them peculiar, but others +common to the next division.</p> + +<br> + + +<center><small>MIDDLE EOCENE FORMATIONS OF FRANCE.</small></center> + +<p><b>Calcaire Grossier, upper and middle, B.1,</b> <a href= +"#page 252">Table</a>—The upper division of this group +consists in great part of beds of compact, fragile limestone, with +some intercalated green marls. The shells in some parts are a +mixture of <i>Cerithium, Cyclostoma,</i> and <i>Corbula</i>; in +others <i>Limnea, Cerithium, Paludina,</i> etc. In the latter, the +bones of reptiles and mammalia, <i>Palæotherium</i> and <i> +Lophiodon,</i> have been found. The middle division, or calcaire +grossier proper, consists of a coarse limestone, often passing into +sand. It contains the greater number of the fossil shells which +characterise the Paris basin. No less than 400 distinct species +have been procured from a single spot near Grignon, where they are +imbedded in a calcareous sand, chiefly formed of comminuted shells, +in which, nevertheless, individuals in a perfect state of +preservation, both of marine, terrestrial, and fresh-water species, +are mingled together. Some of the marine shells may have lived on +the spot; but the <i>Cyclostoma</i> and <i>Limnea,</i> being land +and fresh-water shells, must have been brought thither by rivers +and currents, and the quantity of triturated shells implies +considerable movement in the waters.</p> + +<p>Nothing is more striking in this assemblage of fossil testacea +than the great proportion of species referable to the genus <i> +Cerithium</i> (see <a href="../images1/fig158.jpg">p. 245</a>). There +occur no less than 137 species of this genus in the Paris basin, +and almost all of them in the calcaire grossier. Most of the living +<i>Cerithia</i> inhabit the sea near the mouths of rivers, where +the waters are brackish; so that their abundance in the marine +strata now under consideration is in harmony with the hypothesis +that the Paris basin formed a gulf into which several rivers +flowed.</p> + +<p>In some parts of the calcaire grossier round Paris, certain beds +occur of a stone used in building, and called by the French +geologists “Miliolite limestone.” It is almost entirely +made up of millions of microscopic shells, of the size of minute +grains of sand, which all belong to the class Foraminifera. +Examples of some of these are given in Figs. 219 to 221. As this +miliolitic stone never occurs in the Faluns, or Upper Miocene +strata of Brittany and Touraine, it often furnishes the geologist +with a useful criterion for</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 275">[ 275 ]</a></p> + +<center><img src="../images1/fig219.jpg" width="323" height="197" alt= +"Fig. 219: Calcarina rarispina, Fig. 220: Spirolina stenostoma, Fig. 221: Triloculina inflata."> +</center> + +<p>distinguishing the detached Eocene and Upper Miocene formations +scattered over those and other adjoining provinces. The discovery +of the remains of Palæotherium and other mammalia in some of +the upper beds of the calcaire grossier shows that these land +animals began to exist before the deposition of the overlying +gypseous series had commenced.</p> + +<p><b>Lower Calcaire grossier, or Glauconie grossiere, B.1,</b> <a +href="page 252">Table</a>—The lower part of the calcaire +grossier, which often contains much green earth, is characterised +at Auvers, near Pontoise, to the north of Paris, and still more in +the environs of Compiègne, by the abundance of nummulites, +consisting chiefly of <i>N. lævigata, N. scabra,</i> and <i> +N. Lamarcki,</i> which constitute a large proportion of some of the +stony strata, though these same foraminifera are wanting in beds of +similar age in the immediate environs of Paris.</p> + +<img src="../images1/fig222.jpg" width="179" height="100" alt= +"Fig. 222: Nerita conoidea." align="right"> + +<p><b>Soissonnais sands, or Lits coquilliers, B.2,</b> <a href= +"#page 252">Table</a>—Below the preceding formation, shelly +sands are seen, of considerable thickness, especially at +Cuisse-Lamotte, near Compiègne, and other localities in the +Soissonnais, about fifty miles N.E. of Paris, from which about 300 +species of shells have been obtained, many of them common to the +calcaire grossier and the Bracklesham beds of England, and many +peculiar. The <i>Nummulites planulata</i> is very abundant, and the +most characteristic shell is the <i>Nerita conoidea,</i> Lam., a +fossil which has a very wide geographical range; for, as M. +d’Archiac remarks, it accompanies the nummulitic formation +from Europe to India, having been found in Cutch, near the mouths +of the Indus, associated with <i>Nummulites scabra.</i> No less +than 33 shells of this group are said to be identical with shells +of the London clay proper, yet, after visiting Cuisse-Lamotte +and</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 276">[ 276 ]</a></p> + +<p>other localities of the “Sables inférieurs” +of Archiac, I agree with Mr. Prestwich, that the latter are +probably newer than the London clay, and perhaps older than the +Bracklesham beds of England. The London clay seems to be +unrepresented in the Paris basin, unless partially so, by these +sands.*</p> + +<br> + + +<center><small>LOWER EOCENE FORMATIONS OF FRANCE.</small></center> + +<p><b>Argile Plastique, C.2,</b> <a href="#page 252"> +Table</a>—At the base of the tertiary system in France are +extensive deposits of sands, with occasional beds of clay used for +pottery, and called “argile plastique.” Fossil oysters +(<i>Ostrea bellovacina</i>) abound in some places, and in others +there is a mixture of fluviatile shells, such as <i>Cyrena +cuneiformis</i> (<a href="../images1/fig216.jpg">Fig. 216</a>), <i> +Melania inquinata</i> (<a href="../images1/fig216.jpg">Fig. 216</a>), +and others, frequently met with in beds occupying the same position +in the London Basin. Layers of lignite also accompany the inferior +clays and sands.</p> + +<p>Immediately upon the chalk at the bottom of all the tertiary +strata in France there generally is a conglomerate or breccia of +rolled and angular chalk-flints, cemented by siliceous sand. These +beds appear to be of littoral origin, and imply the previous +emergence of the chalk, and its waste by denudation. In the year +1855, the tibia and femur of a large bird equalling at least the +ostrich in size were found at Meudon, near Paris, at the base of +the Plastic clay. This bird, to which the name of <i>Gastornis +Parisiensis</i> has been assigned, appears, from the Memoirs of MM. +Hébert, Lartet, and Owen, to belong to an extinct genus. +Professor Owen refers it to the class of wading land birds rather +than to an aquatic species.†</p> + +<p>That a formation so much explored for economical purposes as the +Argile plastique around Paris, and the clays and sands of +corresponding age near London, should never have afforded any +vestige of a feathered biped previously to the year 1855, shows +what diligent search and what skill in osteological interpretation +are required before the existence of birds of remote ages can be +established.</p> + +<p><b>Sables de Bracheux, C.3,</b> <a href="#page 252"> +Table</a>—The marine sands called the Sables de Bracheux (a +place near Beauvais), are considered by M. Hébert to be +older than the Lignites and Plastic clay, and to coincide in age +with the Thanet Sands of England. At La Fère, in the +Department of Aisne, in a deposit of this age, a fossil skull has +been found of a quadruped called by Blainville <i>Arctocyon +primævus,</i> and</p> + +<p class="fnote">* D’Archiac, Bulletin, tome x; and +Prestwich, Quart. Geol. Journ., 1847, p. 377.<br> +† Quart. Geol. Journ., vol. xii, p. 204, 1856.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 277">[ 277 ]</a></p> + +<p>supposed by him to be related both to the bear and to the +Kinkajou (<i>Cercoleptes</i>). This creature appears to be the +oldest known tertiary mammifer.</p> + +<p><b>Nummulitic Formations of Europe, Asia, etc.</b>—Of all +the rocks of the Eocene period, no formations are of such great +geographical importance as the Upper and Middle Eocene, as above +defined, assuming that the older tertiary formation, commonly +called nummulitic, is correctly ascribed to this group. It appears +that of more than fifty species of these foraminifera described by +D’Archiac, one or two species only are found in other +tertiary formations whether of older or newer date. <i>Nummulites +intermedia,</i> a Middle Eocene form, ascends into the Lower +Miocene, but it seems doubtful whether any species descends to the +level of the London clay, still less to the Argile plastique or +Woolwich beds. Separate groups of strata are often characterised by +distinct species of nummulite; thus the beds between the lower +Miocene and the lower Eocene may be divided into three sections, +distinguished by three different species of nummulites, <i>N. +variolaria</i> in the upper, <i>N. lævigata</i> in the +middle, and <i>N. planulata</i> in the lower beds. The nummulitic +limestone of the Swiss Alps rises to more than 10,000 feet above +the level of the sea, and attains here and in other mountain chains +a thickness of several thousand feet. It may be said to play a far +more conspicuous part than any other tertiary group in the solid +framework of the earth’s crust, whether in Europe, Asia, or +Africa. It occurs in Algeria and Morocco, and has been traced from +Egypt, where it was largely quarried of old for the building of the +Pyramids, into Asia Minor, and across Persia by Bagdad to the +mouths of the Indus. It has been observed not only in Cutch, but in +the mountain ranges which separate Scinde from Persia, and which +form the passes leading to Caboul; and it has been followed still +farther eastward into India, as far as eastern Bengal and the +frontiers of China.</p> + +<p>Dr. T. Thompson found nummulites at an elevation of no less than +16,500 feet above the level of the sea, in Western Thibet. One of +the species, which I myself found very abundant on the flanks of +the Pyrenees, in a compact crystalline marble (<a href= +"../images1/fig223.jpg">Fig. 223</a>) is called by M. d’Archiac +<i>Nummulites Puschi.</i> The same is also very common in rocks of +the same age in the Carpathians. In many distant countries, in +Cutch, for example, some of the same shells, such as <i>Nerita +conoidea</i> (<a href="../images1/fig222.jpg">Fig. 222</a>), accompany +the nummulites, as in France. The opinion of many observers, that +the Nummulitic formation belongs partly to the cretaceous era, +seems chiefly to</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 278">[ 278 ]</a></p> + +<p>have arisen from confounding an allied genus, Orbitoides, with +the true Nummulite.</p> + +<center><img src="../images1/fig223.jpg" width="326" height="202" alt= +"Fig. 223: Nummulites Puschi."></center> + +<p>When we have once arrived at the conviction that the nummulitic +formation occupies a middle and upper place in the Eocene series, +we are struck with the comparatively modern date to which some of +the greatest revolutions in the physical geography of Europe, Asia, +and Northern Africa must be referred. All the mountain-chains, such +as the Alps, Pyrenees, Carpathians, and Himalayas, into the +composition of whose central and loftiest parts the nummulitic +strata enter bodily, could have had no existence till after the +Middle Eocene period. During that period the sea prevailed where +these chains now rise, for nummulites and their accompanying +testacea were unquestionably inhabitants of salt water. Before +these events, comprising the conversion of a wide area from a sea +to a continent, England had been peopled, as I before pointed out +(p. 267), by various quadrupeds, by herbivorous pachyderms, by +insectivorous bats, and by opossums.</p> + +<p>Almost all the volcanoes which preserve any remains of their +original form, or from the craters of which lava streams can be +traced, are more modern than the Eocene fauna now under +consideration; and besides these superficial monuments of the +action of heat, Plutonic influences have worked vast changes in the +texture of rocks within the same period. Some members of the +nummulitic and overlying tertiary strata called <i>flysch</i> have +actually been converted in the central Alps into crystalline rocks, +and transformed into marble, quartz-rock, micha-schist, and +gneiss.*</p> + +<p><b>Eocene Strata in the United States.</b>—In North +America the Eocene formations occupy a large area bordering the</p> + +<p class="fnote">* Murchison, Quart. Journ. of Geol. Soc., vol. v, +and Lyell, vol. vi, 1850. Anniversary Address.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 279">[ 279 ]</a></p> + +<p>Atlantic, which increases in breadth and importance as it is +traced southward from Delaware and Maryland to Georgia and Alabama. +They also occur in Louisiana and other States both east and west of +the valley of the Mississippi. At Claiborne, in Alabama, no less +than 400 species of marine shells, with many echinoderms and teeth +of fish, characterise one member of this system. Among the shells, +the <i>Cardita planicosta,</i> before mentioned (<a href= +"../images1/fig191.jpg">Fig. 191</a>), is in abundance; and this +fossil and some others identical with European species, or very +nearly allied to them, make it highly probable that the Claiborne +beds agree in age with the central or Bracklesham group of England, +and with the calcaire grossiere of Paris.*</p> + +<p>Higher in the series is a remarkable calcareous rock, formerly +called “the nummulite limestone,” from the great number +of discoid bodies resembling nummulites which it contains, fossils +now referred by A. d’Orbigny to the genus <i>Orbitoides,</i> +which has been demonstrated by Dr. Carpenter to belong to the +foraminifera.† That naturalist, moreover, is of opinion that +the Orbitoides alluded to (<i>O. Mantelli</i>) is of the same +species as one found in Cutch, in the Middle Eocene or nummulitic +formation of India.</p> + +<p>Above the orbitoidal limestone is a white limestone, sometimes +soft and argillaceous, but in parts very compact and calcareous. It +contains several peculiar corals, and a large Nautilus allied to +<i>N. ziczac</i>; also in its upper bed a gigantic cetacean, called +<i>Zeuglodon</i> by Owen.‡</p> + +<p>The colossal bones of this cetacean are so plentiful in the +interior of Clarke County, Alabama, as to be characteristic of the +formation. The vertebral column of one skeleton found by Dr. +Buckley at a spot visited by me, extended to the length of nearly +seventy feet, and not far off part of another backbone nearly fifty +feet long was dug up. I obtained evidence, during a short +excursion, of so many localities of this fossil animal within a +distance of ten miles, as to lead me to conclude that they must +have belonged to at least forty distinct individuals.</p> + +<p>Professor Owen first pointed out that this huge animal was not +reptilian, since each tooth was furnished with double roots (<a +href="../images1/fig224.jpg">Fig. 224</a>), implanted in corresponding +double sockets; and his opinion of the cetacean nature of the +fossil was afterwards</p> + +<p class="fnote">* See paper by the Author, Quart. Journ. of Geol. +Soc., vol. iv, p. 12; and Second Visit to the United States, vol. +ii, p. 59.<br> +† Quart. Journ. of Geol. Soc., vol. vi, p. 32.<br> +‡ See Memoir by R. W. Gibbes, Journ. of Acad. Nat. Sci. +Philad., vol. i, 1847.</p> + +<p> </p> + +<hr> +<p class="page"><a name="page 280">[ 280 ]</a></p> + +<center><img src="../images1/fig224.jpg" width="411" height="227" alt= +"Fig. 224: Zeuglodon cetoides, Fig 225: Basilosaurus."></center> + +<p>confirmed by Dr. Wyman and Dr. R. W. Gibbes. That it was an +extinct mammal of the whale tribe has since been placed beyond all +doubt by discovery of the entire skull of another fossil species of +the same family, having the double occipital condyles only met with +in mammals, and the convoluted tympanic bones which are +characteristic of cetaceans.</p> + +<br> +<hr> +<small><a href="contents.html">Contents</a> / <a href="ch15.html"> +Chapter XV</a> / <a href="ch17.html">Chapter XVII</a></small> +</body> +</html> + |