CLIMATE OF THE PROTEROZOIC 343 



the Proterozoic in the vicinity of Cobalt, Ontario. This inter- 

 pretation, long doubted, now appears to be warranted. It may be 

 noted that glacial formations are singularly out of harmony with 

 the conceptions of the climate of early geologic time which have 

 prevailed until recently. They are altogether in harmony with the 

 conceptions of climate which grow out of the planetesimal theory. 



Map studies. Map studies should be carried on in connection with the chapters 

 on the Archeozoic and Proterozoic. For this purpose, numerous folios of the U. S. 

 Geological Survey are especially serviceable. See also Laboratory Exercises in 

 Structural and Historical Geology, Salisbury and Trowbridge, Exercise VII. 





