162 The American Geologist. March, (220% 
amount of these sands. In case the same chemical processes 
attacked these sands throughout their extension, we should 
doubtless find the greatest deposits of the Mesabi ore in the 
western extension of this Taconic col. 
There is, therefore, no theoretic reason to expect that the 
Mesabi ore is near its exhaustion. On the contrary, the pres- 
ent productive area can hardly be expected to be its greatest, 
but new discoveries are likely to greatly enhance its volume 
and its geographic range. 
Minneapolis, July 20, 1901. 
NEW EVIDENCES OF EPEIROGENIC MOVEMENTS 
CAUSING AND ENDING THE ICE AGE. 
By WARREN UPHAM, St. Paul, Minn. 
The evidences of great epeirogenic uplifts which are ascer- 
tained by soundings of fjords and of river valleys on the sub- 
marine slopes of North America, Europe, and western Africa, 
belonging to the Pleistocene period, far surpass the ordinary 
geologic record of epeirogenic movements through long pre- 
ceding periods and in the recent and present time. From the 
submerged valleys or channels of the Hudson river and the St. 
Lawrence, of numerous rivers then flowing into the Pacific 
from California, of the Adour off the southwestern coast of 
France, and of the Congo off the African coast south of the 
equator, as also from many other such submerged channels 
along the border of these continents, it is known that during | 
the latest geologic period, which in its culmination was char- 
acterized by the accumulation of the North American and 
European ice-sheets, these great land areas of three continents 
were elevated 3,000 to 6,000 feet, or more, higher than now.* 
*Several papers in which the evidences of epeirogenic movements causing 
glaciation have been considered by the present writer are as follows: 
seaman Age in North America, by Pror. G. F, WRIGHT, 1889; appendix, pp. 
Ls eo. 
m a amnaa Geol, Soc. of America, vol. i, for 1889, pp. 563-7; vol. x, 1898, pp. 
AM. GEOLOGIST, vol. vi, pp. 327-339, Dec., 1890; vol. xxii, pp, 101-108, § 
Aug., 1898, treating of the fords and submerged valleys of Europe. 4 | 
Proc., Am. Assoc. Adv. Science, vol. xli, 1892, pp. 171-3, treating of the 
Casao submarine valley and the “Bottomless Pit," off the coast of western 
ca. 
Very important early papers assigning land elevation as the cause of the 
Ice Age were published by DANA and LECONTR, and this view is well stated in 
their text-books of geology. 
