A HISTORY OF SCIENCE 



longer be denied. Nor could it be in doubt that the 

 successive faunas, whose individual remains have been 

 preserved in myriads, representing extinct species by 

 thousands and tens of thousands, must have required 

 vast periods of time for the production and growth of 

 their countless generations. 



As these facts came to be generally known, and as it 

 came to be understood in addition that the very ma- 

 trix of the rock in which fossils are imbedded is in 

 many cases one gigantic fossil, composed of the re- 

 mains of microscopic forms of life, common - sense, 

 which, after all, is the final tribunal, came to the aid of 

 belabored science. It was conceded that the only 

 tenable interpretation of the record in the rocks is that 

 numerous populations of creatures, distinct from one 

 another and from present forms, have risen and passed 

 away ; and that the geologic ages in which these creat- 

 ures lived were of inconceivable length. The rank and 

 file came thus, with the aid of fossil records, to realize 

 the import of an idea which James Hutton, and here and 

 there another thinker, had conceived with the swift in- 

 tuition of genius long before the science of paleontol- 

 ogy came into existence. The Huttonian proposition 

 that time is long had been abundantly established, 

 and by about the close of the first third of the last 

 century geologists had begun to speak of "ages" and 

 "untold aeons of time" with a familiarity which their 

 predecessors had reserved for days and decades. 



CHARLES LYELL COMBATS CATASTROPHISM 



And now a new question pressed for solution. If the 

 earth has been inhabited by successive populations of 



