Glaciation of Mountains, Etc. — W. Upliam. 207 
inches long, corresponding in mineral structure with the 
ledges in Randolph and Jefferson, twelve or fifteen miles away. 
The general color of the rock is so like that of the mountain 
that one would not perceive the difference between them with- 
out close inspection. The mica is arranged differently in it ; 
The white parts are more abundant, though in fine grains, and 
the rock is evidently the same with the upper member of what 
I call the 'Bethlehem gneiss' in the New Hampshire reports. 
The highest point at which stones of foreign origin were 
obtainable may be twenty or twenty-five feet below the very 
pinnacle of the mountain. Hence it is fair to conclude that 
every part has been covered by the glacial ice. . . . Just 
beyond the signal-station dwelling I found a flat ledge sloping 
a little northwesterly, but precipitous on the southeast. At- 
mospheric agencies have marred the surface so much that no 
strife are visible, even if they ever existed. I had proposed to 
scrutinize every harder projection of quartz with a lens as this 
course sometimes reveals striation where other inspection is 
unavailing. Were this ledge situated near the Lake of the 
Clouds, where embossment is common, I should point it out 
unhesitatingly as an example of ice-sculpture, though much 
degraded by weathering. The shape agrees with that of thous- 
ands of glaciated ledges in other parts of the state. Other 
ledges on the mountain farther north resemble this one. Inas- 
much as the transportation of materials is clearly proved by 
the presence of the Jeff'erson rock upon the summit a few rods 
away, it will not be unreasonable to believe that this apparent 
embossment is real. The altitude of the ledge is the same with 
that of the site of the travelled stones. The disposition of the 
large blocks upon the summit is noteworthy. Several acres 
of surface are covered by them far away from visible ledges. 
As you approach a ledge, it is easy to see what fragments have 
been separated by frost action, as the projections match the 
indentations. . . ." 
Before this discovery, while it was believed that Mt. Wash- 
ington and its neighbors rose above the ice- sheet at its time of 
greatest thickness, professor Dana had computed, from the 
slope of the ice-surface thus known, and from the courses of 
striation and transportation of bowlders in Canada, that the 
elevation of the surface of the ice-sheet over the northern 
border of New England was about 8.000 feet, and over the 
