THE AGE OF THE EARTH FROM THE GEOLOGICAL 



VIEWPOINT. 



By T. C. CHAMBERLIN. 



{Read April 22, 1922.) 

 General Introduction. 



In pioneer days, when the sciences were struggling for a place in 

 the sun, it fell to Geology to pull up and set back the stakes that man 

 had stuck to mark the beginning of the earth. This seemed to many 

 a moving of sacred landmarks; to others it seemed a wanton use of 

 the secrets of the cemetery of nature's dead. A bitter war arose : 

 racial bias disputing the rock beds ; tradition and sentiment fighting 

 mud layers and fossil imprints. The struggle that followed was long. 

 The throwing of rocks and rock-ribbed arguments grew to be an art 

 that might well have drawn forth the envy of an Ajax. But the 

 substantial slowly gained on the sentimental. The brutal cogency of 

 a slab of fossils could be hated and fought, but could not be gainsaid. 

 And as the tide turned, the geologist began to play crusader; he 

 mounted his war horse and went forth to convert the world — includ- 

 ing, withal, some of his scientific colleagues. 



After a time, however, the battle shifted to another field. Darwin 

 and Wallace drew off a following and taught them to use the subtler 

 weapons of "the struggle for existence" and "natural selection." 

 However, they still plied the old geologic weapons, for they, too, had 

 reason to point to bed on bed ; they had need of even more time than 

 the geologists. So they took the lead and the team became a tandem. 

 Biology prancing in front, Geology trotting on in the thills. 



But the spirit and abandon of this team soon awakened a new 

 antagonist. Kelvin took the field in the name of Physics, Astronomy 

 and Mathematics, and sought to set metes and bounds to the back- 

 ward extension of terrestrial time. He told the tandem, with much 

 show of premises and figures, that the feed on hand positively would 



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PROG. AMER. PHIL. SOC, VOL. LXI, R, DEC. 26, I922. 



