Slviii PBOCEEDINGS OP THE GEOLOGICAL SOCIETY. 



Triassie beds of St. Cassian ; Nautilacese begin in the Lower Palae- 

 ozoic, and are still existing ; Amnionitidae begin with the Upper 

 Devonian series, and cease with the Chalk • Belemnitidse are of still 

 younger date, first appearing with the Lias, and ending with the 

 Chalk ; while the Sepiadse and Teuthidae from the same date of origin 

 are continued to the present ocean, with the Argonaut, which is 

 unknown below the Tertiaries. In the case of the Orthooerata, 

 which die out and seem to be replaced by Belemnites, we have a 

 type of the many successive substitutions which this class of Mol- 

 lusks exhibits for study. 



Thus in the Ammonitaceee, Goniatites is followed by Ceratites, this 

 by the Arietes, these by the Falciferi, these by Coronarii, Macroce- 

 phali, Dentati, Oniati, Flexuosi, &c, which and several other 

 groups occupy definite stages in the Lias, Oolites, and Cretaceous 

 deposits*. The successive sets of forms cannot, I think, be deduced 

 from the preceding ones : yet some real succession appears among 

 the Ammonites — in their sutures, so well examined by Yon Buch — 

 and among the Belemnites, of which the Liassic, Oolitic, and Cretaceous 

 groups may be for the most part very well and easily distinguished. 



§ Succession of Life. 



The conclusion, that the most remarkable combinations of the 

 natural objects whose remains are found in the earth depended, like 

 the phases of human society, upon elapsed time modified by local 

 conditions — in this respect also like the changes of the families of 

 mankind, — this conclusion by no means closes the inquiry or solves 

 the problem of life on the globe. 



In all parts of nature we perceive, and acknowledge with reverence 

 and delight, the most happy adjustments of structure and function ; 

 very often, adaptations of singular beauty to suit residence in air or 

 water; not seldom, special organization and habits fitted for parti- 

 cular works or constructions, or peculiar local conditions. " Com- 

 moda quibus utimur, luce qua, fruimur, a Deo nobis dari videmus." 



Zoology, botany, and physiology are full of these manifestations 

 of coordination of the structures and functions, of habits of life and 

 physical conditions ; and no well-reasoning mind can resist the con- 

 viction that the innumerable contrivances and coordinations which 

 are discovered in nature are evidence of a higher power of thought 

 than our own, an unlimited command of those forces of which we 

 can only measure the sensible effect in time and space, and an in- 

 tentional guidance of the complicated machine of creation by fixed 

 general laws, which hold together in harmony an incalculable variety 

 of variable elements. 



Can we discover these laws ? 



Perhaps not. The process of induction, by which alone we can 

 hope to reach a sure basis of theory, may be incomplete through 



* See my Treatise on Geology, 1832, Encyel. Metrop. ; also ' Guide to 

 Geology,' and the articles " Goniatites" and " Turrilites" which I communi- 

 cated to the ' Penny Cyclopaedia.' 



