442 FRANK BURSLEV TAYLOR 
On the whole, the character of the oscillation as one that 
was always accompanied by a readvance after recession seems 
to be well established by several different lines of evidence and 
by several of the most experienced observers. 
THE PROBABLE RATE OF ICE-SHEET MOTION. 
The great ice-cap of Greenland bears a closer analogy to our 
own Pleistocene ice-sheet than any other ice mass yet studied. 
The observations of Peary, Chamberlin, Salisbury, and others 
throw no uncertain light on the problems of ice-sheet motion as 
there exhibited. On this point Professor Chamberlin says: 
Lieutenant Peary has commenced a series of observations upon the 
movements of glaciers of the Inglefield Gulf region, both by instruments and 
by photographs taken at intervals. He found the daily movement of the 
Bowdoin glacier, the most active in the immediate vicinity of his headquar- 
ters, during the month of July to be four-tenths of a foot at the slowest point, 
and 2.78 feet at the fastest point, near the center, with an average of 1.89 
for the whole.* 
The movement of the majority of the glaciers in that region is very 
much slower; indeed, in most cases it is obviously exceedingly slow. Many 
of the ordinary signs of movement are absent. In front of the Fan glacier 
there are cones of granular ice brought down by the surface streams, and 
also embankments of old snow, soiled, granulated, and half solidified into 
ice, as though at least a year eld, all of which lie banked against the ter- 
minal face of the glacier without any indication of movement on its part 
since their formation. As these lean against the face to heights of thirty or 
forty feet at least, it is obvious that there had been no melting of the base of 
the extremity to counteract the effects of advance. Phenomena of similar 
import were observed in several other glaciers. The very firm impression 
was given by such physical signs that the average rate of movement of the 
glaciers of the region is very slow. At the head of the gulf are a few 
glaciers which produce large icebergs and which must be notable exceptions 
to the prevailing slowness of motion.” 
t According to Professor Chamberlin (JOUR. GEOL., Vol. V, No. 3, 1897, pp. 229- 
232), the Bowdoin glacier is six or eight miles long, about two miles wide in its lower 
part and descends between 2000 and 3000 feet. After its separation from the ice-cap 
by a somewhat steep fall, the Bowdoin glacier becomes essentially Alpine in type. 
Hence it does not furnish a criterion that can be applied to the ice-cap itself. Slow 
as is the advance of the Bowdoin glacier, it is probably much faster than that of the 
edge of the main ice-cap. 
2 Recent Studies in Greenland, Bull. G.S. A., Vol. VI, 1895, pp. 216-217. 
