154 C. W. Hayes — Expedition through the Yukon District. 



these the eastern appears to be retreating much more rapidly 

 than either of the others ; but this eastern branch probably has 

 its source in the same basin as the Frederika glacier, and it seems 

 not improbable that by some means the drainage of the basin 

 has been diverted from the western to the eastern outlet, thus 

 causing the rapid retreat in the former glacier and advance in 

 the latter. 



The large trijjle glacier above referred to flows from the high 

 mountains forming the eastern members of the Wrangell group. 

 After the union of its three branches the combined stream occu- 

 pies the valley of the Nizzenah for about six miles, crowding the 

 river out of its channel and forming a berg-filled lake above the 

 ice barrier. Its great volume, together with the distance which 

 this glacier pushes down into the valley, indicate an increased 

 precipitation, due to proximity to the Copper River valley through 

 which pass the w^arm winds from the ocean. 



No glaciers flow into the Chittenah valley from the ranges on 

 either side, though all the upper portions of the Wrangell group 

 are snow-covered and doubtless the high ravines are filled with 

 ice. Several large glaciers flow into the Copper River valley 

 from the Coast range, although its altitude is not so great as that 

 of many portions of the interior 2:)lateau, which is entirely free 

 from summer snow. The largest of these Coast range tributaries 

 of Copper river are Miles and Childs glaciers, named by Lieu- 

 tenant Allen in 1885. Several others of considerable size higher 

 up the river do not appear on Allen's map, probably because he 

 passed up the river while the surface was still covered with snow. 

 Miles glacier is quite comparable in size with those of the St 

 Elias region and is formed under essentially the same climatic 

 conditions. It is evidently retreating at present, and the river 

 spreads out in a lake-like expansion along its front in a part of 

 the glacial channel from which the ice has receded. This ex- 

 pansion of the river is about a mile in width and one side is 

 formed by the glacier front, a cliff of ice 350 feet above the water 

 and over five miles in length. Although the ice no longer 

 reaches entirely across the valley, there remains a heavy lateral 

 moraine, indicating its former position and damming back the 

 river as already described. The fact that the river has cut only 

 part way through the moraine indicates a very recent recession 

 of the glacier. 



