266 GANNETT 



Pacific side, swings around from northwest to southwest, 

 thus following the general course of the coast. Of the 

 great features of the territory this chain forms the south- 

 ernmost, and is the key to the structure of the country. 

 Succeeding it on the north is the great valley of the Yukon, 

 which is separated from the Arctic coast by ranges of low 

 mountains and broken country probably nowhere exceed- 

 ing 5,000 or 6,000 feet in altitude. 



The Cordillera attains its greatest breadth and altitude 

 between longitudes 142 and 152. Here are many sum- 

 mits reputed to exceed 12,000 feet in height, with Mount 

 Wrangell, said to be 17,500 feet, and Mount McKinley, 1 

 so far as known the highest summit on the North Amer- 

 ican continent, rising to an altitude of 20,464 feet. In 

 this portion of the mountain system are the sources of 

 many large rivers, the White, a branch of the Yukon, the 

 Copper, well named on account of the enormous deposits 

 of copper ore found near it, the Sushitna, flowing into the 

 head of Cook Inlet, the Tanana, another branch of the 

 Yukon, and finally the Kuskokwim, which, heading in the 

 western part of this group, flows southwest into Bering 

 Sea. In the region north of the Yukon valley originate 

 many streams, including several large branches of the 

 Yukon, as the Porcupine and Koyukuk; other streams, 

 as the Noatak and Kowak, flow into Kotzebue Sound, 

 and still others, as the Colville, flow northward into the 

 Arctic Ocean. 



The country is intersected by a network of rivers and 

 lakes navigable for canoes, although navigation is much 

 interrupted by rapids and falls. The great highway of the 

 territory is the Yukon River, which, heading in British 

 Columbia, flows northwestward through a succession of 

 lakes and rapids, and crosses the boundary line in latitude 

 65. It reaches its most northern point just on the Arc- 

 latitude 63, longitude 149. 



