A MOXTH WITH THE MUIR GLACIER 49 



The character and course of the moraines on the eastern 

 half of the glacier also attest its slower motion. There are 

 seven medial moraines east of the north-and- south line, four 

 of which come in to the main stream from the mountains to 

 the southeast (see Fig. 24). Xear the rim of the glacial am- 

 phitheatre these are long distances, in some cases miles, 

 apart ; but, as they approach the mouth of the amphitheatre, 

 they are crowded closer and closer together near its eastern 

 edge, until in the throat itself they are indistinguishably 

 mingled. The three more southern moraines unite some dis- 

 tance above the mouth. One of these contains a large 

 amount of pure marble. This moraine gradually approaches 

 the others on either side until the distance between them 

 disappears, and its marble unites with the other material to 

 form one common medial moraine. The fifth moraine from 

 the south is about 150 yards in width, five miles back from 

 the mouth. It is then certainly as much as five and prob- 

 ably eight miles from the mountains from which the debris 

 forming it is derived. All these moraines contain many 

 large blocks of stone, some of which stand above the general 

 mass on pedestals of ice, with a tendency always to fall over 

 in the direction of the sun. One such block was twenty feet 

 square and about the same height, standing on a pedestal of 

 ice three or four feet high. It is the combination of these 

 moraines, after they have been crowded together near the 

 mouth, which forms the deposit now going on at the north- 

 east angle of the inlet just in front of the ice. Of this more 

 will be said in connection with the question of the recedence 

 of the glacier. Similar phenomena, though on a smaller 

 scale, appear near the southwest angle of the amphitheatre. 



The dominant streams of ice in the glacier come from 

 the north and the northwest. These unite in the lower por- 

 tion to form a main current, about one mile in width, which 

 is moving toward the head of the inlet with great relative 

 rapidity. Were not the water in the inlet deep enough to 

 lloat the surplus ice away, there is no knowing how much 

 farther down the vallev the glacier would extend. The 



