302 GENERAL OBSERVATIONS. 



in rocks, are more or less ancient, and differ more or less from 

 the present animals and vegetables, according as they are lower or 

 higher in the series of strata. Such authors speak of different races 

 being successively created and destroyed; each succeeding race 

 approaching nearer to the present genera and species. According to 

 them, there was first a world of zoophytes; and this being de- 

 stroyed was followed by a world of cockles, or such like bivalves ; 

 which cockle world being also ruined, was succeeded by a world of 

 crocodiles or huge lizards, destined to perish in their turn, to make 

 way for other creations ; a few stragglers from each lower world 

 being allowed, however, to ascend and hold a station in the world 

 next above : but all the inhabitants of these numerous worlds 

 became extinct, before the creation of man, and his present fellow- 

 tenants of the globe. Some go so far as to assert, that not one fossil 

 species agrees exactly with any living species ; except a few species 

 found in the alluvium, which by peculiar favour have obtained a kind 

 of apotheosis, having ascended from the world last destroyed, to 

 figure in the present. — ^These notions, which seem to have gained 

 currency chiefly through their novelty and their wildness, it is impos- 

 sible to reconcile with facts. No such gradation exists; but we see 

 in all the beds, whether high or low, organized substances that have 

 recent analogues, and others that have not; and find as large a pro- 

 portion of the latter in the oolite and the chalk, as in the aluminous 

 strata. Zoophytes abound most in the chalk and the oolite, while in 

 the lowest shale we see oysters and other shells, corresponding in 

 every respect with living species. Indeed, there are some shells, 

 particularly ostracites, ammonites, and belemnites, that exist in al- 

 most all the strata containing organic remains. They occur in the 

 chalk and the oolite, and in the lowest shale: nay, they occur in much 

 loiver, or to use the common phrase, older strata; for Dr. MaccuUoch 

 discovered belemnites in Garvh island, in limestone alternating with 



