344 Canadian Record of Science. 



On Some Granites from British Columbia and 



the Adjacent Parts of Alaska and 



the Yukon District. 



By Frank D. Adams, Lecturer in Geology, McGttl University. 



Some three years ago, when on the staff of the Geological 

 Survey of Canada, the writer was requested by Dr. G. M. 

 Dawson, to examine a series of rock specimens collected by 

 that gentleman and his assistants, Messrs. McConnell and 

 Ogilvy, during their explorations in the Yukon Districts 

 and Northern British Columbia in 1887. The results of 

 this examination were published as an appendix to Dr. 

 Dawson's Report on the Yukon District. 1 



The rocks examined were, for the most part granites, 

 but included also, diabase porphyrites, diabase tuffs and 

 other rocks, which, however, were normal in character, 

 and possessed of no features which here deserve especial 

 mention or farther description. 



Among the granites, however, there were three which 

 were rather remarkable and seemed to be worthy of a 

 more extended study than it was at that time possible to 

 make. I have accordingly, through the kindness of Dr. 

 Dawson, re-examined the hand specimens, and with the aid 

 of additional thin sections have made a more detailed study 

 of the rocks in question. 



Granite from Wrangell Island, Alaska. — The first of these 

 rocks is a rather fine grained grey granite from Wrangell 

 Island, Alaska. In Dr. Dawson's Report it is referred to as 

 follows : " The rocks along the west shore of "Wrangell 

 Island, in the vicinity of the town and harbor, are chiefly 

 black flaggy argillites, remarkably uniform and regular 

 in their bedding and with a westward dip. They are con- 

 siderably indurated and contain small staurolite crystals 

 in some layers, while on the surface of others crystals 



1 Appendix V. Notes on the Lithological Character of some rocks collected in 

 the Yukon District and adjacent Northern parts of British Columbia, by Frank 

 D. Adams. Annual Report of the Geological Survey of Canada 1887. 



