OF THE ORGANIC FOSSILS. 427 



former; since we do not know what the past con- 

 ditions of the earth were. Recent researches have 

 discovered more resemblances than were once thought 

 to exist, and further ones will prohahly add to these. 

 If indeed the remote revolutions destroyed all the 

 existing races, we might conclude that all the distant 

 ones were extinct; yet we could not even then 

 prove the asserted want of correspondence, without 

 assuming, what we can never know, that new ones 

 were not produced on the same models. The former 

 is a difficult question of geology; the latter is a purely 

 metaphysical and vain speculation. It is better to 

 examine the facts, imperfect as they are, and to rest 

 on them for the present. Yet there are difficulties 

 and uncertainties in such investigations, founded on 

 the ignorance of naturalists as to the genera of Nature ; 

 while they perpetually forget that their own are often 

 artificial, the conveniences of Nomenclature; even 

 forgetting their own laudable anxiety to discover the 

 real plan of Creation. 



A few facts must here suffice. Echini, terebratulae, 

 turbines, chamas and tellinae, occur as existing genera, 

 and are also found in the primary argillaceous schist. 

 Anorniae, patellae, nautili, and crabs are living genera, 

 and also fossils in the lowest limestone. In the lias, 

 chama, donax, helix, trochus, asteria, and many more, 

 are living genera; and proceeding upwards to the 

 chalk, we find, of the latter, balanus, pholas, buc- 

 cinurn, turbo, patella, pecten, murex, pinna, and 

 others, together with tortoises, besides the amphibia 

 formerly mentioned. Any catalogue will furnish 

 farther generic identities. That of De France, gives, 

 among other conclusions, a hundred and ninety six 

 genera living and fossil both, and a hundred and 

 fourteen fossil only. Whatever interest to zoology the 



