568 THE JOURNAL OF GEOLOGY. 
melted back, leaving a moat-like ditch between the eminence 
and the mass of the glacier surrounding it, not unlike the defen- 
sive trench of an ancient castle. Whenever the motion of the 
ice is considerable, however, this intervening space is absent and 
the ice impinges forcibly upon the base of the prominence. 
So striking a feature could not well escape the notice of pre 
vious visitors to the region. In the Greeley reports the designa- 
tion ‘‘Chinese Wall” is aptly applied to it. Its significance and 
especially the internal structure and mode of action which it 
reveals were not unnaturally overlooked amid the engrossing 
demands of other interests. 
Stratification—This melting back of the edge of the ice, 
developing a vertical face in the place of the usual slope, is a 
matter of the utmost good fortune to the glacial student, as it 
displays the basal organization of the ice and reveals its methods 
of work to a degree that could scarcely have been anticipated. 
It is as though a Titan with the blade of a giant knife, one or 
two hundred feet long, had sliced away the border of the glacier, 
giving us a vertical section across the end and along both sides. 
This truncation of the edge reveals a remarkable stratification of 
the ice and an equally remarkable insetting of rock débris. The 
stratification of glaciers is by no means an unknown phenomenon, 
but I doubt whether it had ever been suspected that it reaches 
an extent and an intimacy such as is here displayed. As will be 
readily seen from the accompanying photographic illustrations; 
the ice is not only arranged in layers, but these are subdivided in 
a very intimate fashion, so intimate indeed in many portions as 
to pass beyond simple stratification in its usual sense and become 
lamination. In extreme instances the thin layers number as many 
as twenty to the inch. By turning to the illustrations (Figs. 31, 
33 and 35,in particular) it will be seen that there is a thick 
stratum of clean, white ice at the top, beneath which there is a 
zone of ice darkened with much débris, and at the bottom a talus 
slope.formed from a mixture of ice and rock fallen from above, 
commingled with the residue of snow drifts. The talus slope 
rises to heights of thirty and forty feet, and occasionally more. 
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