6 G. F. Wright—T. he Muir Glacier. 
3. The Moraines. 
The character and course of the moraines on the eastern half 
of the glacier aiso 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 south- 
east. (See fig. 2.) Near the rim of the glacial amphitheatre 
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 distance above the mouth. 
One of these contains a large amount of pure marble. This 
moraine approaches the others on either side until the distance 
between them disappears, and its marble unites in one common 
medial moraine a mile or more above the mouth. 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 
probably eight, miles from the mountains from which the debris 
forming it was 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 andabout 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 northeast angle of the 
inlet just in front of the ice. Of this I will speak more fully 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. 
4. Indirect evidences of Motion. 
The dominant streams of ice in the Muir glacier come from 
the north and the northwest. These unite in the lower portion 
to form a main current, about one mile in width, which is mov- 
ing toward the bead of the inlet with great relative rapidity. 
Were not the water in the inlet deep enough to float the sur- 
_ plus ice away, there is no knowing how much farther down the 
valley the glacier would extend. The streams of ice from the 
east and southwest have already spent the most of their force 
on reaching the head of the inlet; and, were it not for this 
central ice-stream, a natural equilibrium of forces would be 
established here independent of the water, and no icebergs 
would be formed. The surface of this central current of mo- 
tion is extremely rough, so that it is entirely out of the ques- 
tion to walk far out upon it. On approaching this portion of 
