56 ASSINNIBOINE AND SASKATCHEWAN EXPEDITION, 



Winnipeg as it now is. The whole of this immense 

 denuded tract of country is a splendid instance of the 

 power of water and ice to remove many thousand cubic 

 miles of rock. 



It is very probable that before the Boulder Drift period, 

 the chain of mountains beginning with Turtle Mountain 

 near the forty-ninth parallel, and terminating with the 

 Porcupine and Pasquia Eanges, including the Eiding, 

 Duck, and Thunder Mountains, were part of a high table 

 land, composed of Cretaceous and Tertiary rocks, which 

 extended from the Grand Coteau de Missouri to the 

 Laurentides. The areas most affected by denudation are 

 now occupied by Lakes Winnipeg, Manitobah, Winnipe- 

 go-sis, and the valleys of their tributaries. The precipitous 

 eastern escarpment of the chain of mountains show the 

 action of oceanic agencies to which they would be directly 

 exposed, if the country were submerged to more than 

 1000 feet, and from the distribution of boulders, there 

 can be no question that a submergence to a far greater 

 extent has taken place since the Tertiary epoch. The 

 connection of these ranges will be best seen by an in- 

 spection of the map.* 



The summit of the Eiding Mountains is a vast table 

 land declining in steps to the Assinniboine. The forest 

 which covers the upper plateau consists of very fine 

 white spruce, birch, poplar, and aspen ; the circumferences 

 of some of the trees about our camp, measured five feet 

 from the ground, were as follow : — Aspen, 4 ft. 6 in., 

 4 ft. 6 in., 4 ft. 1 in., 3 ft. 9 in., 5 ft. ; White Spruce, 

 7 ft. 3 in., 5 ft. 6 in., 6 ft. 6 in., 6 ft. ; Birch, 3 ft. 6 in., 

 3 ft. ; Poplar, 4 ft. 9 in., 4 ft. 6 in. These trees repre- 

 sent, as far as my observations permitted me to judge, the 



* Vide Chapter on the surface geology of the valley of Lake Winnipeg. 



