OF GEOLOGICAL DYNAMICS. 103 



" out of loose data." To the second of these sen- 

 tences I assent, but certainly not to the first. I have 

 riot presented definite results ; I have amply indi- 

 cated how " loose " my data are ; and I have taken 

 care to make my results looser. Professor Huxley 

 himself in otJier parts of his address has complained 

 of their vagueness " as greatly embarrassing the 

 discussion." If I had presumed to limit the past 

 duration of life on the earth to one million years 

 or to ten million years, by calculations, founded on 

 such data as I have used, so ill drawn an inference 

 could scarcely " embarrass " those who are still 

 disposed to trust to " a practically unlimited bank 

 " of time ready to discount any amount of hypo- 

 " thetical paper." But it is obvious that they must 

 be seriously embarrassed by even a superior limit 

 of four hundred million years : especially when the 

 declaration of it is coupled with the assertion of a 

 very strong probability that " all geological history 

 showing continuity of life," is in reality to be 

 condensed into a period not exceeding one hundred 

 million years. 



22. Before concluding, I may be permitted to 



