540 



INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



in origin and believed to be Carboniferous in age, in the southern part of Vancouver, which 

 forms part of the same axis of elevation with the Queen Charlotte Islands, it is highly probable 

 that the rocks of this age may come to the surface in sonae places. Mr. Whiteaves, who has 

 examined the fossils, does not find any clearly Triassic forms among those from Rose Harbor, 

 the old copper mine in Skincuttle Inlet, and the south end of South Island in Skidegate Inlet. 

 The limestones of these localities may therefore possibly be of Carboniferous age, and if so a 

 large portion of the associated rocks of volcanic origin must be attributed to the same period. 

 As it is at present impossible to unravel the structural complexity of the sub-Cretaceous rocks 

 of the islands, it has been thought best to color them together on the map as Triassic, in , 

 correspondence with their characteristic fossils. 



Though no report is here made on observations in the northern part of Vancouver Island, 

 it may be mentioned that Triassic forms identical with those from one of the localities on 

 Houston Stewart Channel, have been obtained on Forward Inlet and Browning Creek, Quatsino 

 Sound. 



Any unconformity which may have existed between different beds of this sub-Cretaceous 

 mass of rocks may now be masked by their complete folding and the great disturbance and 

 fracture to which they have been subjected. The occurrence of great masses of contempo- 

 raneous volcanic material during both the Triassic and Carboniferous periods, in British Colum- 

 bia, has been demonstrated in former reports ; and in the event of the lower and possibly Car- 

 boniferous rocks proving to be really Triassic, their general character would accord closely 

 enough with that of those known elsewhere. 



sp 5p ^ r^ jp 5p 5p jp SfC 



Tabular view of formations represented in the Queen Charlotte Islands. 



Post-Pliocene. 



Sands and gravels. 



Plastic and bowlder clays, gravel bods, etc. 



Unconformity", with, evidence of some flexure and disturbance of Tertiary beds. 



Tertiary, probably Miocene. 



Volcanic rocks of the north part of Graham Island. 

 Sandstones, with marine fossils and lignites of Skunun Point. 

 Shales, clays, and lignites of Ma-min Kiver and Chin-oo-kun-dl Creek. 



Complete unconformity, with evidence of great disturbance. Chief period of mountain making. 



Cretaceous. 



A. Upper shales and sandstones. 



B. Coarse conglomerates. 



C. Lower shales and sandstones. 



D. Agglomerates. 



E. Lower sandstones. 



Unconformity, but without evidence of great disturbance. 



Triassic, but possibly passing below into Carbon- 

 iferous. 



Agglomerates and ash rocks of Logan Inlet, etc. (These possibly 



represent subdivision D, supra.) 

 Flaggy calcareous argillites and thin limestones. 

 Massive limestones. 

 Massive dioritic and feldspathic volcanic accumulations, probably 



including minor limestone beds, occasionally schistose. 



TRIASSIC. 



The rocks seen in the shores of Houston Stewart Channel are everywhere very much 

 disturbed, shattered by faults, and traversed by innumerable dikes. This region lies in the 

 line of the mountainous axis of the islands, and though no extensive granitic masses appear 



