it* 



n*uivt 



ORGANIC REMAINS. 



ISO 



oil. eanl. rrevl. * *Trna. In which, not uncommonly, pottery. 

 fclriiHil boo-, and other mark* of rod* civilisation accompany the 

 reUqvw of oar progenitor*. If thi* absence of the We. of mm 

 (row UM sjwriae itn 



strata were the only evidence which geology had to 

 UM comparatively late creation of man, we might 

 sr error which from time to time is revived by specu- 

 acquainted with the progrew of science, the error of 

 the human nee, for whom the present aspect and 

 of the globe U adapted, the *ame antiquity of origin as 

 irrous tribes of plants and animals which became extinct 

 UM birth of man, and were adapted to other and earlier 

 of the planet. 



Z^tHeerie* of At CtatWf o/ rerfeorai A*iaU. 



i 



Trntur 



- 



CkrkoalftroM 



luce a few of the proof* necessary to the establishment 

 of this truth, by determining first, what are the- degree* of analogy to 

 existing now presented by the organic fossil* of the different systems 

 of strata. As before observed, the remains of terrestrial plants and 

 animals occur too rarely, and in a certain sense too accidentally, in 

 tbe strata of marine origin to be of much importance in this reasoning. 

 Taking then oar example* chiefly from marine trib-s, we may state 

 that in the Paleozoic Strata none of the species are known to be now 

 living, and about two-third* of them belong to genera which are also 

 Among these extinct genera are the whole group of Trilobita, 

 same, Gmiutilm, Ortkoctrata, Phraymocerata, &c, Producta, 

 and many laowlliferou* corals. 



All tbe specie* in the Carboniferous System are hi the same manner 

 extinct, and fully half of the marine tribe* belong to extinct genera, 

 often identical with those in the Pataozoic Series. Here we find some 

 hundred* of terrestrial plant* (Ltpidodmtl ,-on, Stigmaria, &c.), now 

 entirely unknown among the 80,000 which botanists are acquainted 

 with. Nearly tbe same proportion of tbe species found in the Salife- 

 rous and Oolitic Systems (about 40 per cent.) belongs to extinct genera 

 (all the species being unknown in modern oceans). Among these 

 we have the gigantic ivptile form*, the Enaliosaurians, the 

 the iltgalotaurui : the counties* Crphalopod*, Ammonites, 

 ; many Crinoidea and Kchinida, besides plants approach- 

 tacto Zamiu, y*ueim, and tropical Ferns. 



The Cretaceous System, in like manner, contains many extinct 

 Men (JTeswrara*, Turrilita, Scapkila, AnanchyUt, Mampita, Ac.), 

 ta which about 40 per cent of the specie* yet found may be ranked. 

 All the epcciM are distinct from existing tribe*. 



Bat hi the Tertiary Strata, which crown the aerie* of marine 

 deposits, a different result has rewarded the diligent comparison 

 between foesU and recent specie*. The great number of shells in 



ana of judgment, and M. Deshayw 

 has in eonesqoenoe bean able to establish very exact inference*. In 

 UM oldest of UM TerUsriw (Eocene deposits of Lyell) there occur 

 from S to 6 per cent of existing species. In those of middle age 

 (Mioeens deposits) from 7 to 88 (avenging 18) per cent ; but in the 

 jpnsimost seriw of Tertiariw (Pleiocene deposit*) from 40 to 96 per 



Tbua, by estimates, M exact as can be made, of the whole number 

 of species, geologists are enabled to perceive clearly that the affinity 

 t*>sisu fewil and resent species of animal* and plants is greatest in 

 UM most rteent strata, least in UM most ancient, and in general is 

 vmely proportional to UM antiquity of tbe strata. Not only man 

 is absent from UM fossil world of life, but nearly all the actual creation 

 I* wanting UMTS, and is replaced by the relics of other and earlier 



and compsrin* the organic remains which fill the 



of strata, we find that, as few living forms appear 



ong UM lower terUaries, few or none of UM tertiary forms appear 

 UM lower parts of UM Cretaceoos System : thi* system is hi the 

 same manner distinct from the maw of the oolites, these from the 

 rail essHstonie, the latter from UM carboniferous rocks, and all from 

 tte palsMoic group*. 



Seek of UMW systems of strata contains UM remains of animals and 

 ' were in existence in the sea, in fre.li waters, or on the 



and, at or previous to the time of the production of those strata; and 

 by combining the evidence derived from all we arrive t a view, it 

 plete indeed, yet not necessarily inaccurate, of the succession of organic 

 life upon the globe. 



It is perhaps a common opinion that the earliest forms of life, those 

 which occur in the foasiliferous primary (or pahcozoic) rocks, are of 

 simpler organisation than inch a* belong to later periods ; and a con- 

 jectural view of the succession of organic life on the globe obscurely 

 hint* at a gradual complication of animal and vegetable organisations 

 in proportion to the elapsed time. In favour of thU view, the first 

 occurrence of Fishe* in Uie uppermost of the Silurian Strata, and the 

 first occurrence of Reptiles in the lower beds of the Magneaiau Lime- 

 stone Formation deserve consideration. But, on the other hand, it is 

 not to be concealed that the earliest fishes which do appear exhibit 

 analogies to reptile structure, and betray no mark of inferior organi- 

 sation ; and the earliest remains of reptiles belong to high grade* of 

 that class. 



On referring to the most ancient known British fossils, those few 

 which lie in the slates of Snowdonia, we find them to consist of 

 Lamelliferous Polypi/era and Brachiapoda, such as LinytUa, Producta, 

 and Spin/era* small assortment certainly, and thus perfectly in 

 harmony with the view of the gradually increasing numerical amount 

 of fossil forms already explained, but not such as to justify a state- 

 ment of their inferiority of organisation. In the next stage of organic 

 life, the Silurian System, the fossil species amount to several hundreds, 

 and among them are many Polypifera, many Echinodtrmata, Brachio- 

 poda, and other Conclufera,Gaiteropoda, and Cephalopoda, with Cruttacea 

 and Fishe*. It cannot be said that these organisations, compared with 

 others of the same class now living, are, in any just sense, inferior or 

 lew complex ; nor do we find reason to qualify this assertion while 

 reviewing the similar and larger series of fowils from the Carbonifer- 

 ous System, in which KUhes become numerous and varied in structure. 



If we pursue this subject, the result of our inquiries is to mtablish 

 the fact of the successive introduction of all the classes and most of 

 the great divisions of marine animals in the successive geologies! 

 periods, not by the improvement or expansion of one original general 

 type, but by addition of new organisations to meet new physical 

 conditions of the globe. 



This important result, which presents to us a series of great revolu- 

 tions in organic life anterior to the desiccation of our present land 

 (which is the bed, or rather exhibits many successively obliterated 

 beds of the ancient seas, with their extinct inhabitants), and adapted 

 to the chain of physical phenomena which preceded and prepared 

 the actual arrangements of nature, may be confirmoU by n brief notice 

 of the duration of certain extinct races, By this expression it i- in-t 

 meant to state or to insinuate definite periods of time, but the space 

 occupied on a scale of successive geological events, by the whole 

 traceable duration of particular races of animals. For this purpose 

 we shall take two genera of Brachiopotla (Producia, Spirifei-a), four of 

 Cephalopoda (Ooniatitos, Orthoceras, Ammonites, Belemnites), three 

 of Criutacea (Catymene, AtapHtu, Qlyphia), three of Fishes (//otopty An*, 

 Polaoniictu, Tetrogonolepii), and three of Reptiles (Ichthyotaurtu, 

 Pterodactyltu, and Mototauriu). The systems of strata being, as 

 before, represented by horizontal lines, and the particular fossils 

 ranged in vertical columns, the asterisks denote the occurrence and 

 geological duration of the groups. 



Here then is a representation of very numerous facts known to 

 geologist*, which demonstrate that each group of extinct organisation, 

 each genus of such a group, each species of such a genus, has a 

 definite geological range, appears at a particular point in the scale of 

 geological event*, and cease* at another point. From these facta, 

 investigated and collected, it is a clear and positive inference that, 

 during the period which elapsed in the production of the stratified 

 rocks, many combinations of animal* and plants in this sense many 

 systems of organic life came into being and passed away, not by 

 violent catastrophe* or universal revolutions, but by partial substitu- 

 tions distinctly traceable, often coincident with or consequent on 



