Prof. J. W. Spencer—Ice Action in the North. 121 
closet-geology in America, in order to make personal observations of 
the phenomena associated with modern glaciers, —for comparison with 
those in the region of our Great Lakes, often attributed to land-ice. 
My conclusions—that simple land glaciers are not great eroding 
agents—are greatly strengthened, not merely by the observations of 
many other geologists, but particularly by those of various explorers 
in high latitudes—some of which are given here. 
2. Herr Payer! states that the snow-line in Franz Josef Land 
descends to within 1000 feet of the sea (this is lower than is known 
anywhere else in the Arctic regions), and that numerous glaciers 
discharge great quantities of icebergs into the sea. He says :— 
“ However diligently I looked for them, I never saw unmistakable 
traces of grinding and polish of rocks by glacial action.” . 
3. Lieutenant Lockwood? found in Central Grinnell Land a thick 
ice-cap extending for a distance of 70-90 miles or more, faced by 
an ice-wall of a nearly uniform height of 125-200 feet, irrespective 
of topographical inequalities. It was quite free from rock-débris, 
except in a valley confined by mountainous walls, thousands of feet 
high. Along its foot there was almost an absence of morainic ridges, 
and even where present these deposits were unimportant fragments. 
The general absence of rocks and dirt in the Arctic glaciers is com- 
mented on by General Greely, who observed them only in two or 
three glaciers. The glaciation about Lake Hazen was not recent. 
The snow-line in this high latitude of Central Grinnell Land is 
3800 feet above the sea. 
4, In Spitzbergen, with a lower snow-line, Baron Nordenskjéld * 
found striated rock-surfaces only below 1000 feet. The same holds 
good with regard to Labrador, where mountains rise 6000 feet, whilst 
the glaciation has not been observed above 1000-1600 feet (Dr. R. 
Bell).+ 
5. In the Antarctic regions, the officers of the “Challenger” ° 
remarked the absence of débris in the icebergs seen ; although Ross 
in his Antarctic voyage examined volcanic rocks upon some of them. 
These volcanic blocks are supposed to have come from valleys in the 
mountains. 
6. Indeed, outside the valleys, explorers in high latitudes have 
not found the tools for great erosion in the margins of the ice-caps 
visited. The continental area of North America presents much 
lower and less abrupt prominences than the reliefs of Greenland, 
Grinnell Land, Spitzbergen, or Franz Josef Land. Overhanging 
mountains seem to be necessary to furnish tools to land glaciers, by 
which alone any abrasion can be accomplished, and these conditions 
belong only to the valleys of great mountain ranges. 
7. However, there is one condition, under which glaciers when 
shod with graving tools ought to be great eroders,—namely, when 
1 « New Lands within the Arctic Circle,’’ 1872-74, Payer. 
2 ««Three Years of Arctic Service,” 1881-84, Greely. 
3 See GrotocicaL Macazine, 1876. 
4 Hudson’s Bay Expedition of 1884. 
° Notes by a Naturalist of the ‘‘ Challenger,’’ 1879, Moseley. 
