Groundwork for Study of Megadiastrophism. 273 



deposits and are no more evidence of an original molten 

 state than the great granitic intrusions of Jurassic age 

 along our western coast, as recently remarked by Cole- 

 man. 16 And then came radioactivity and robbed the 

 molten theory of almost its only resource for actuating 

 diastropliism, viz. : the cooling of the earth ; while close 

 on the heels of this came the seismic waves and their allies 

 which are now heaping up irrefragible evidence that, if 

 there ever was a molten state, it is now a thing of the past, 

 and that the great dynamic problems of the day, diastro- 

 pliism, metamorphism, asthenozones, magmatic genera- 

 tion, vulcanism, isostasy, paleogeography, and the like, 

 must all be worked out on the basis of a solid elastic earth. 

 If the molten earth is an issue at all in present day 

 problems, apparently it can be only in the sense of an 

 issue over the estate left behind by the departed. 



10 A. P. Coleman, Xature, vol. 109, p. 775, June 17, 1922. 



Universitv of Chicago, 

 Julv 19, 1922. 



