198 PHYSICAL GEOGRAPHY. 



Long enumerates thirty affluents of the Red River, and 

 its western branch, the Assinaboyn. 



The Saskatchewan, which is to be considered as the 

 main feeder of the Winipeg basin, flows from a consider- 

 able distance above Pine Island Lake down to Lake 

 Winipeg over horizontal beds of limestone, through so 

 flat a country that the river forks as it would in an allu- 

 vial delta. A rich mud is deposited in parts, particularly 

 between Pine Island Lake and the main stream, and round 

 Moose and Muddy Lakes. In Beaver Lake, which lies 

 immediately to the north of Pine Island Lake, the silurian 

 strata are again seen covering the flanks of the primitive 

 rocks ; while to the southward an eminence named Bas- 

 quiau*, lying at the distance of nearly a degree, sepa- 

 rates the river valley from the Red Deer Lake and Swan 

 River. As powerful salt springs exist on this eminence, 

 we may conjecture that it belongs to the Onondago salt 

 group. 



I have been more particular in the topographical 

 and geological remarks on the St. Lawrence and Saskat- 

 chewan basins, because economy of space made it expe- 

 dient to omit the details of the voyage of the Expedition 

 through them. The remaining districts will be more 

 briefly mentioned here, since the narrative included many 

 facts relating to them. 



VALLEY OF THE MISSINIPI. 



The next river basin that we have to notice is that of 

 the Churchill, English River, or Missinipif, the latter, or 



* See Journal, I. p. 68. 



| Mist or mitchi, in Cree, signifies "much or great," and nipi 

 " water," while sipi means " river." 



