A MOXTH WITH THE MUIR GLACIER. 67 



the tunnel itself is now deserted for some distance by the 

 stream, so that the debris is caving down into the bed of the 

 old tunnel as the edges of ice melt away, thus forming a 

 tortuous ridge, with projecting knolls where the funnels into 

 the tunnel are oldest and largest. At the same time, the ice 

 on the sides at some distance from the tunnel, where the 

 superficial debris was thinner, has melted down much below 

 the level of that which was protected by the thicker deposit ; 

 and so the debris is sliding down the sides as well as into the 

 tunnel through the center. Thus three ridges approximately 

 parallel are simultaneously forming — one in the middle of 

 the tunnel and one on each side. When the ice has fully 

 melted away, this debris will present all the complications of 

 interlacing ridges, with numerous kettle-holes and knobs 

 characterizing the kames ; and these will be approximately 

 parallel with the line of glacial motion. The same condition 

 of things exists about the head of the subglacial stream on 

 the east side, also near the junction of the first branch glacier 

 on the east with the main stream, as also about the mouth of 

 the independent glacier shown on the map lower down on the 

 west side of the inlet (see Fig. 24). The formation of kettle- 

 holes in the terminal ridges has already been referred to. 



Considerable earthy material is carried out from the front 

 by the bergs. Pebbles and dirt were frequently seen frozen 

 into them as they were floating away. Just how many of the 

 bergs were formed from ice that originally rested on the bot- 

 tom of the inlet I have no means of telling. That some were 

 so formed seems exceedingly probable, if for no other reasons 

 because of the great amount of debris that was sometimes 

 seen frozen into them. It is by no means certain that the 

 subglacial streams boiling up near the upper corners of the 

 inlet were beneath the lowest stratum of ice. Some small 

 streams were seen pouring out from the face of the ice half- 

 way up from the water. It seems likely that a great amount 

 of sediment is conveyed into cavities in the center of the 

 glacier through the action of these subglacial streams ; and 

 so is ready for transportation when the masses break loose. 



