162 PHYSICAL GEOGKAPHY. 



to me. When treating of districts which I did not visit, 

 I have borrowed from every work concerning them to 

 which I had access. The most important sources of in- 

 formation are generally named or expressly alluded to; 

 but I thought that it would give too much formality to 

 so slight a sketch were I to parade every authority for the 

 statements it contains. Where practised geologists have 

 examined the country, their report has been chosen in 

 preference to my own observations; and this is the case 

 on the route of the expedition up to the 49th parallel. 

 Beyond Lake Winipeg no geologist has yet penetrated, 

 and the descriptions of the rocks occurring within the 

 space of twenty degrees of latitude that lie to the north of 

 that sheet of water are, with all their imperfections, entirely 

 my own. It would be true economy in the Imperial Go- 

 vernment, or in the Hudson's Bay Company, who are 

 the virtual sovereigns of the vast territory which spreads 

 northwards from Lake Superior, to ascertain without 

 delay the mineral treasures it contains. I have little 

 doubt of many of the accessible districts abounding in 

 metallic wealth of far greater value than all the returns 

 which the fur trade can ever yield. 



The Rocky Mountain chain, which is the northern 

 prolongation of the Andes, has a general course of north 

 26° W. for 2,700 geographical miles, from the 30th 

 parallel of latitude up to the shores of the Arctic Sea. 

 Its higher peaks rise from 12,000 to 15,000 feet above the 

 ocean, and enter the region of perpetual snow ; but the 

 northern part of the chain, which touches on the Mac- 

 kenzie, is so much lower, that even its summits * are 

 denuded during the short summer of that district, and 

 perennial patches of snow exist there only in shady cre- 



* Supposed to be at least 3,000 feet high, in the 62nd parallel. 



