CRITERIA OF GLACIATION 



623 



V\K- 515- The radiation of striae in the area of the Green Bay glacial lobe and 

 in the west part of the Lake Michigan lobe, during the last glacial epoch. 



The true theory of the drift must explain all the foregoing facts 

 and relations. Any hypothesis which fails to explain them all must 

 be incomplete, and any hypothesis with which these facts and rela- 

 tions are inconsistent must be false. Geologists are now agreed 

 that glacier ice, supplemented by the agencies which it calls into 

 being, is the only agent which could have produced the drift. This 

 does not preclude the belief that at various times and places in the 

 course of the ice period, icebergs were formed, or that locally and 



