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G. M. DAWSON ON THE SUPERFICIAL GEOLOGY OE 



21. Additional Observations on the Superficial Geology of British 

 Columbia and adjacent Regions. By George M. Dawson, 

 D.Sc, F.G.S., Assoc. B.S.M., Assistant Director of the Geological' 

 Survey of Canada. (Read March 9, 1881). 



Contents. 



Observations on the Southern part of the Interior of British Columbia. 



Observations north of the 54th parallel in British Columbia. 



Peace and Athabasca Basins. 



Additional Notes on the Coast. 



Glaciation of the Queen -Charlotte Islands. 



General Eemarks and Conclusions. 



In two papers previously communicated to the Geological Society, 

 the results of observations on the glaciation of the northern portion 

 of the American continent from Lake Superior to the . Pacific have 

 been given*. The geological work of which these observations 

 formed a part was carried on first in connexion with the North- 

 American Boundary-Commission Expedition, and subsqu entry on the 

 Geological Survey of Canada. In continuing the exploration of 

 British Columbia on the Survey last named, during the seasons of 

 1877, 1878, and 1879, many additional facts of interest have been 

 gathered, which it is proposed here briefly to summarize and discuss 

 with special reference to the second of the two papers above men- 

 tioned, in which a description of the salient physical features of the 

 province of British Columbia has been given, and a map published ; 

 to these, which it is unnecessary here to repeat, reference should be 

 made in considering the points now brought forward. 



Observations on the Southern part of the Interior of British Columbia. 



In the more detailed examination of that part of the southern 

 portion of the province extending from the Eraser eastward to the 

 Gold ranges, and including the whole breadth of the region formerly 

 called the interior plateau, traces of a general north-to-south 

 glaciation have been found in a number of additional localities at 

 high levels ; and it would appear that the ice, whether that of a great 

 glacier or water-borne, pressed forward to, or even beyond, the line 

 of the 49th parallel, notwithstanding the generally mountainous 

 character of that part of the country. "With the facts previously 

 recorded, these now extend the known area of north-to-south 

 glaciation to a portion of the plateau over 400 miles in length. 



The most striking instance of this general glaciation, and that 

 which carries it up to a height greater than elsewhere observed, 

 is met with in the case of Iron Mountain at the junction of the 

 Nicola and Coldwater rivers. This mountain is one of the more 

 prominent points of that portion of the plateau, which, toward the 

 eastern or inland borders of the coast-range, becomes rough and 

 broken. It rises in a broad dome-like form to a height of 3500 

 * Quart. Journ. Geol. Soc. vol. xxxi. p. 603, and vol. xxxiv. p. 89. 



