"The Stickeen Glaciers 



ones that lay in my way were crossed on sliver bridges 

 or avoided by passing around them. The structure of 

 the glacier was strikingly revealed on its melting sur- 

 face. It is made up of thin vertical or inclined sheets 

 or slabs set on edge and welded together. They repre- 

 sent, I think, the successive snowfalls from heavy 

 storms on the tributaries. One of the tributaries on 

 the right side, about three miles above the front, has 

 been entirely melted off from the trunk and has re- 

 ceded two or three miles, forming an independent 

 glacier. Across the mouth of this abandoned part of 

 its channel the main glacier flows, forming a dam 

 which gives rise to a lake. On the head of the de- 

 tached tributary there are some five or six small 

 residual glaciers, the drainage of which, with that of 

 the snowy mountain slopes above them, discharges 

 into the lake, whose outlet is through a channel or 

 channels beneath the damming glacier. Now these 

 sub-channels are occasionally blocked and the water 

 rises until it flows alongside of the glacier, but as the 

 dam is a moving one, a grand outburst is sometimes 

 made, which, draining the large lake, produces a 

 flood of amazing power, sweeping down immense 

 quantities of moraine material and raising the river 

 all the way down to its mouth, so that several trips 

 may occasionally be made by the steamers after the 

 season of low water has laid them up for the year. 

 The occurrence of these floods are, of course, well 

 known to the Indians and steamboat men, though 

 they know nothing of their cause. They simply re-r 

 mark, "The Dirt Glacier has broken out again." 



[ loi 1 



