AGKICULTTJEAL DEVELOPMENT IN ALASKA. 3 



that forms the drainage area of the Yukon River and is occupied by- 

 innumerable detached mountains and mountain masses. There are 

 no extensive level plains and very little level land, this being limited 

 to the alluvial bottom lands along the larger streams, notably the 

 Yukon Flats. 



The northern or Arctic mountain system, most clearly defined in 

 the Endicott Range, is a continuation of the Rocky Mountains, the 

 Continental Divide, which, continuing northwestward through 

 Canada, reaches the northern coast of the continent near the boundary 

 between Canada and Alaska, and then swinging sharply to the west 

 extends across the northern portion of Alaska. The altitudes in this 

 system within Alaska are not high, the maximum being not more 

 than 6,000 feet, with the result that there is but a small perpetual 

 snow and ice field. The northern slope toward the Arctic Ocean is a 

 barren and for the most part unexplored wilderness. It is drained 

 by a number of large rivers. 



The Pacific mountain system, which fronts the south coast of 

 Alaska, demands more attention, for it is not only that which has 

 developed public opinion regarding Alaska, but it is the dominating 

 physical factor. It is the extension of the Coast Range of the 

 United States, with which the Sierra Nevada coalesces in northern 

 California and continues northward through Oregon and Washing- 

 ton as the Cascade Mountains. North of Puget Sound the sea has 

 broken into the mountain fastnesses along a 1, 000-mile stretch until 

 the St. Elias Range is reached, where, with increasing height, the 

 sea is forced back outside of the coast line. Northwestward from 

 Mount St. Elias the range widens into a system, with the Chugach 

 and Kenai Mountains immediately on the coast, and back of these 

 the Wrangell and Nutzotin Mountains. These, with the minor 

 ranges, merge into the Alaskan Range that swings southwestward 

 and continues out on the Alaska Peninsula as the Aleutian Range, the 

 whole mass forming the arc of a great circle. The system, extend- 

 ing in width from the water's edge to 200 miles back from the coast, 

 is of great altitude, the maximum being Mount McKinley, in the 

 Alaskan Range, 20,464 feet. Mount St. Elias is 18,024 feet high, and 

 Mount Blackburn, in the Wrangell Mountains, is 16,140 feet. 



Right here in this mountain mass, occupying an area 200 by 

 400 miles in extent, is the dominating fact that always must be borne 

 in mind when studying Alaska, namely, the effect on the moisture 

 with which the warm air currents from the sea are laden. Striking 

 the cold breasts of these high mountains, the moisture in the air is 

 condensed and precipitated as snow on the high levels and as rain 

 lower down, 90 inches being the average annual precipitation at 

 Sitka, while at a number of points on the coast in southeastern Alaska 



