348 A. E. CAMERON 



re-advance of the ice sheet during the general retreat from the 

 region. The moraines consist of low ranges of irregularly shaped 

 hills, somewhat higher in elevation than the adjacent country, and 

 trend in a general direction at right angles to the movement of 

 the glacier, as shown by glacial striae. The best-developed moraine 

 occurs immediately north of Buffalo Lake. The morainic hills 

 here have an elevation of 200 to 300 feet above the surrounding 

 country, and form a dam behind which the waters draining from the 

 north slopes of Caribou Mountains are ponded, forming the large 

 shallow body of water known as Buffalo Lake. This moraine 

 extends north to within a few miles of Great Slave Lake. Two 

 moraines were noted in the valley of Hay River; one tending to 

 connect the Watt Mountain Plateau with that of Eagle Mountains ; 

 and the other, the Caribou Mountains with Eagle Mountains. 

 The low ridge of glacial drift now existing between Watt and 

 Caribou mountains and forming the present watershed between 

 Peace and Hay rivers appears to be an interlobate moraine formed 

 between two lobes of the waning glacier, 



PROBABLE LAKE EXPANSIONS 



From this somewhat scanty evidence an attempt may be made 

 to outline the various stages of lake formations developed as the 

 continental ice sheet retreated from the region. 



At least three definite glacial lobes are apparent in the area. 

 One extended up the valley of Hay River; a second swung west, 

 south of the Caribou Mountains, and probably sent tongues up 

 the valleys of the Peace and Wabiskaw rivers; while the third 

 lay in the basin of Athabaska Lake with its tongue pointing up 

 the valley of Athabaska River. 



The first stage to be considered (Fig. 11), is when the water 

 level stood at about 1,600 feet. The Hay River lobe extended up 

 the valley to a point south of the sixtieth parallel. The edge of 

 the other lobes is not determinable from the information at hand, 

 but it would appear that the Peace River lobe extended well up 

 toward Vermilion and probably sent a tongue south up the valley 

 of the Wabiskaw to a point close to the twenty-sixth base line; 

 while the Athabaska lobe must have extended at least as far south 

 as this same line. The similarity of elevation of the lake benches 



