Chap. I. 



SUCCESSION OF ANIMALS AND PLANTS. 



93 



exemplification of the manner in which diflercnt species of animals may originate, one 

 from the other, and increase the nnmber of types existing at first? And yet, with all 

 this apparent freedom of transfornuition, what do the facts finally show? That all 

 these transformations are the successive terms of a cycle, as definitely closed within 

 precise limits, as in the case of animals, the progeny of whicli resembles for ever 

 the immediate parent, in all successive generations. For here, as every^vhere in 

 the organic kingdoms, these variations are only the succes.sive expressions of a 

 well regulated cjcle, ever returning to its own type. 



SECTION XXI. 



SUCCESSION OF ANBLVLS AXT) PLANTS IN GEOLOGIC^VL TIMES. 



Geologists hardly seem to appreciate fully, the whole extent of the intricate 

 relations exhibited by the animals and plants whose remains are found in the 

 different successive geological formations. I do not mean to say, that the investi- 

 gations we possess respecting the zoological and botanical characters of these remains 

 are not remarkable for the accuracy and for the ingenuity with which they have 

 been traced. On the contrary, having myself thus far devoted the better part of 

 my life to the investigation of fossil remains, I have learned early, from the difficul- 

 ties inherent in the subject, better to appreciate the wonderful skill, the high 

 intellectual powers, the vast erudition displayed in the investigations of Cuvier 

 and his successors upon the faunae and flora? of past ages.^ But I cannot refrain 



' CrviER, (G.,) Rccherclies sur Ics Ossemcns 

 fossiles de Qiiadriipedes, etc., Paris, 1812, 4 vols. 

 4to. ; nouv. edit. Tiiris, 1821-23, 5 vols. 4to. ; 4e 

 edit. 10 vols. 8vo. and 2 vols. pi. 4to. — Sowkhhy, 

 (James.) The Mineral Conchology of Great 15ritain, 

 London, 1812-19, 6 vols. 8vo. fig. — Scni-OTTiiEiM, 

 (K. F. v..) Die Pefrefactenkiinde, etc., Gotha, 1820, 

 Svo. fig. — Lamauck, (.7. B. DE,) Memoires sur les 

 fossiles des environs de Paris, Paris, 182.'J, 4to. fig. — 

 GoLDFUSS, (G. A.,) Petrcfacta Germanic, Diisscl- 

 dorf, 1826-33, M. fi;r. — Sternberg, (Kaspar, M. 

 Gr. v.,) Versueh einer geognostiscli-botanisclien Dar- 

 Btellung der Flora der A'orwelt, Leipzig und Prag, 

 1820-38, fol. tig. — Brongniart, (Ad.,) Prodrome 

 d'liiK' Ilistoire des Vegetaux fossiles, Piiris, 1818, 



2 vols. 8v(). — Ilistoire des Vegetaux fossiles, Paris, 

 1828-43, 2 vols. 4to. fig. — Lindlet, (J.,) and Hct- 

 TON, (W..) Tlie Fossil Flora of Great Britain, Lon- 

 don, 1831-37, 3 vols. 8vo. — GorPERT, (IL R..) 

 Systenia Filicum fossilium, Vratisl. et Bonnie, 1830, 

 4to. fig. — Die Gattungen der fossilen Pflanzen, ver- 

 gliclicn init dcnen der Jetztwelt, etc., Bonn, 1841- 

 48, 4to. fig. — Monograpliie der fossilen Coniferen. 

 Diisseldorf, 1850, 4to. fig. — More special works are 

 quoted hereafter, but only such works shall be men- 

 tioned, which have led on, in the progress of Geology 

 and Paheontology, or contain full reports of the pres- 

 ent state of our science, and also such as have 

 special reference to America. References to tlie 

 description of species may be found in Bn<»SN', 



