752 T. C. CHAMBERLIN 
was much more extensive than from the other centers, and 
because they were not aided essentially by mountainous points of 
origin, for neither the Labradorean nor the Keewatin centers 
appear to have been initiated by mountainous elevations. It 
was a development of glaciation on plains, or at most on plateaus. 
This fact renders the American ice-fields conspicuously chief 
among all that developed in Pleistocene times. The glaciation 
of Europe was centered upon mountains; and remnants of 
glaciation still linger on the mountain heights of most of the 
old glacial fields, giving ground for the belief that the local 
topographic features were there important factors. The glacia- 
tion of northwestern Europe would possibly have been rather 
scant if it had received no greater topographic aid than was 
afforded in the Keewatin field, but apparently it would not have 
been absent. 
It has often been remarked that the Pleistocene glaciation 
was gathered about the north Atlantic, but it can scarcely be too 
much emphasized that the greatest, of the glacial areas, and by 
far the most phenomenal, because of its plain topography, lies 
on the western, or what we are accustomed to regard as the 
windward, side of the Atlantic. 
It is further to be noted, that on the western side of America, 
the glaciation, though notable, was still seemingly much inferior 
to that of the great northeastern plains; and this in spite of its 
mountainous character and its adjacency to the great Pacific 
Ocean, a topographic and hydrographic conjunction which 
expresses itself now in the most vigorous glaciation outside of 
the polar circles. 
More or less nearly contemporaneous with the growth of the 
foregoing great ice-sheets, local glaciation developed on nearly 
all the mountain heights of the earth, whether in the northern 
or ‘the southern hemisphere, and whether in high or low latitudes. 
Thi’s seems to imply an intensification of glacial conditions gen- 
erally, but at the same time to indicate that the great ice-sheets 
were depyendent on some special agency of localization. In say- 
ing that tilcese scattered areas of glaciation were approximately 
