THE BEGINNINGS OF LIFE. 619 



on he says: c The Foraminiferous Fauna of our own 

 seas probably present a greater range of variety than 

 existed at any previous period ; but there is no indication 

 of any tendency to elevation towards a higher type. 5 



Again, it has been not unreasonably urged by some 

 persons that if the organic world had been really 

 evolved by the agencies which Mr. Darwin seems to 

 believe almost exclusively influential, demands would 

 have to be made upon time of so exorbitant a nature as 

 to frighten even the most liberally disposed geologists 

 and physicists. And this is believed by many to be a 

 matter of some moment. Sir Wm. Thomson 1 , indeed, 

 has given reasons for the opinion that no such vast 

 periods of time can have elapsed since the surface of 

 our earth became sufficiently cool to permit of the 

 presence of living things. He thinks this stage of 

 the Earth's history cannot have been attained more 

 than 400,000,000 of years ago. The subject is, perhaps, 

 one in which the data may be insufficiently known to 

 permit of a reliable calculation being made, though 

 no one could speak with higher authority on such a 

 problem than Sir Wm. Thomson. We may, how- 

 ever, confidently state that the alarming demands 

 for very vast periods of time made by biological evo- 

 lutionists would be materially diminished if views 

 like those which we have advanced were commonly 

 entertained 2 . 



1 ' Trans, of Geolog. Soc. of Glasgow,' vol. iii. 



2 See p. 429, note. 



