GEOLOGICAL EXTERMINATIONS. 



183 



living interest for the naturalist in addition to the other useful 

 points raised in the paper. 



Kev. G. P. Whidborne, M.A.,F.G.S.— I have read Dr. Warring's 

 suggestive paper with very great interest. The extermination of 

 species is self-evident, e.g., Spirifer, Pterodactyle, Ammonites, etc., 

 must have been exterminated. That any living species is descended 

 from them is unthinkable. The many monotremata are now 

 reduced to two. 



That at times extermination was synchronously predominant 

 may also be predicated, without, of course, suggesting that it was 

 at any time complete. There are often rapid disappearances of 

 whole groups of species that never recur in the same profuseness 

 again. At most continuance is accounted for by " survival of the 

 fittest. " But evidently that expression is intrinsically inaccurate ; 

 its meaning is intended to be " survival of the fittest in a modified 

 form." Dr. Warring I understand tells us that the commonly sug- 

 gested causes for these survivals are insufficient, and suggests three 

 others of a chemical character. Whether these in turn are alto- 

 gether adequate for the effects may perhaps be questioned. We 

 have far the most evidence in geological history of sea animals. 

 Their genealogy may be treated alone. Two of Dr. Warring's three 

 causes practically vanish with regard to them. Atmosphere and 

 soil could have had very slight and indirect effects upon them. We 

 have then only the chemical change of the sea to account for their 

 genealogy. Is it sufficient to have produced the evolution ascribed 

 to it 1 For instance, the assumed excess of lime might be sup- 

 posed to have resulted in more massive shells, but as an instance 

 Spiriferina of the Oolites are, speaking generally, more massive than 

 Spirifera of the Devonian. Devonian Gasteropods from Chud- 

 leigh, placed besides recent specimens of similar form, are almost 

 similar in massiveness. But I in no way wish to suggest that Dr. 

 Warring's three causes are not effective, but only that they are not 

 in themselves fully adequate for the effects assigned them. They 

 may come to the help of the other causes asserted to produce evolu- 

 tion ; the result is that we get a still greater variety of assigned 

 causes, and the advantage in Dr. Warring's causes is that a sequence 

 in the causes is at least implied congruous with the sequence of 

 effects, though insufficient in itself to account for them. But what 

 Dr. Warring emphasises is that the sequence of effects is orderly, a 



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