OCR Text |
Show 60 'J.'ERTIARY MAMMIFEROUS REMAINS· (Ch.V, In the Miocene mammalia we find a few of the generic forms most frequent in the Eocene strata associated w.ith so~e of those now existing, and in the Pliocene we find an mt~nmxture of extinct and recent species of quadrupeds. There Is, therefore, a considerable degree of accordance. between the results deducible from an examination of the fossil testacea, and those derived from the mammiferous fossils. But although the latter are more important in respect to the unequivocal evidence afforded by them of the extinction of species, yet, fot· reasons before explained, they are of comparatively small value in the general classification of strata in Geology. It will appear evident, from what we have said in the last volume respecting the fossilization of terrestrial species, that the imbedding of their remains depends on rare casualties, and that they are, for the most part, preserved in detached allu~ vions covering the emerged land, or in osseous breccias and stalagmites formed in caverns and :fissures, or in isolated lacustrine formations. These fissures and caves may sometimes remain open during successive geological periods, and the allu~ vions, spread over the surface, may be disturbed, again and again, until the mammalia of successive epochs are mingled and confounded together. Hence we must be careful, when we endeavour to refer the remains of mammalia to certain tertiary periods, that we ascertain, not only their association with testacea of which the date is known, but, also, that the remains were intermixed in such a manner as to leave no doubt of the former coexistence of the species. In the next page will be found a Synaptical Table of the Recent and Tertiary formations alluded to in this chapter. N. B. By aid of this table, the reader will be able to refer almost all the localities of the Pliocene formations enumerated in the Tables of M. Deshayes (Appendix I.) to the newer or older division of the Pliocene period established in the foregoing chapter. ( Gl ) Synaptical Tuble of Recent and Tertiary Fo·rmations. PE.RIODS. I. lbc&NT. II. TERTIAltY. I. Newer Plioceue. 2, Older Pliocene, 3. Miocene. 4. Eocene. Chnructer I Forr::uons. Locnlltlee of the different Formations. J Marine. Freshwater. ~ Vo!oank. Marine. { Coral formations of Pacific. Delta of Po, Ganges, &c. { Modern deposits in Lake SuperiorLake of Geneva-Marl Jakes of Scotland-Italian travertin, &c. { J orullo - Monte N uovo - Modern lavas of Iceland, Etna, Vesuvius &c. ' { Strata of. the Val di Noto in Sicily. Ischm, Morea? Uddevalla. F1·eshwater. {Valley of the .Elsa around Colle in Tuscany. Volcanic. / Marine. Freshwater. Volcanic. ] Marine. Freshwater. l Voloank / Marine. Freshwater. Volcanic, { Older pn:ts of Vesuvius, Etna, and Isclu~-Volcanic rocks of the Val d1 Noto in Sicily. { Northern Subapenn~ne ~ormations, as at Parma, Ast1, Stenna, Pet·pig~ nan, Nice-English Crag. { Alternating with marine beds near the town of Sienna. { Volca~os of Tuscany and Campagna dt Roma. { Strata of Tourai~e, Bordeaux, Valley of the Bo.rmtda, and the Superga near Turm-Basin of Vienna. { Altemating with marine at Saucats, twdvl:l miles south of Bo1·deaux, { Hungari~n a1~d Transylvanian vol~ cnntc rocks. Part of the volcanos of Auvergne Cantal, and Veluy? ' Paris and Londou Basins. { Alter~nting with marine in Paris basm- Iule of ·wight-purely la~ custrine in Auve1·gne, Can tal and Veiny. ' { Oldest part of volcanic rocks of Auvergne, |