314 BROOKS AND KINDLE PALEOZOIC ROCKS OF UPPER YUKON 



crustal disturbances. Though the Tertiary heds are folded and there 

 have been many orographic movements in this province since Lower Cre- 

 taceoiis times, they belong to a different order of magnitude. These 

 crustal disturbances have done little to obscure the effects of the older 

 crustal movements, which have determined the dominating structural 

 features of the region. It is worthy of note that some of these later 

 crustal movements were accompanied by granitic intrusions which have 

 cut Upper Cretaceous beds. A discussion of the complex recent oro- 

 graphic history of the region, with which is involved the genesis of the 

 land forms, is no part of the purpose of this paper. 



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