374 
The American Geologist. 
June, 1396 
end of lake Superior along the Nemadji river and the lower 
part of the St. Louis river.* 
Lake Ohio. The tract called Beech Flats, in Pike county, 
Ohio, which Prof. G. F. Wright had regarded as a stratified 
delta of the glacial lake Ohio,f has been recently ascertained 
by Prof. W. G. Tight to be a smooth tract of till; J but, ac¬ 
cording to the criteria noted in this paper, it may perhaps 
still be cited as good evidence of that glacial lake held by the 
dam of the ice-sheet crossing the Ohio valley at Cincinnati. 
Thickness of Englacial and finally Superglacial Drift. 
From my observation of traces of stratification throughout 
a long and well exposed section of sublacustrine till at Cleve¬ 
land, Ohio, the thickness of drift which there was englacial 
and at last became superglacial, allowing it to be slightly 
modified by deposition in the water of lake Warren, appears 
to have been at least 15 to 20 feet.§ Stream erosion near the 
outermost' or Altamont moraine in southwestern Minnesota 
during the recession of the ice-sheet implies that there, adja¬ 
cent to especially prominent moraine accumulations, the 
englacial drift amounted to about 40 feetSj Again, from evi¬ 
dence which I think impossible to be otherwise interpreted, 
the esker of Bird’s Hill, seven miles northeast of Winnipeg, 
Manitoba, seems to prove for that vast plain-like region a 
total thickness of 40 feet of englacial drift. 
Altitude of Englacial Drift Transportation. 
Although it may not now be regarded, by some glacialists, 
as consistent with the principles of physics or with the in¬ 
creasing knowledge of the action of existing glaciers and 
ice-sheets, I cannot doubt the testimony of Bird’s Hill, in its 
relations to the adjacent sublacustrine till sheet and to lake 
Agassiz, that the englacial drift there, increased above its 
ordinary amount and perhaps carried to an exceptional hight 
*Geol. Survey of Minnesota, Twenty-second Annual Report, for 1893, 
p. 44, with sections. 
|The Ice Age in North America, 1889, pp. 333, 334, with map. 
^Bulletin of the Scientific Laboratories of Denison University, vol. ix, 
pp. 25-34, with map, Dec., 1895; noticed in the Am. Geologist, vol. 
xvii, p. 326, May, 1896. 
§Bulletin, Geol. Society of America, vol. vii, pp. 329,331, March, 1896. 
j|Geology of Minnesota, vol. i, pp. 603, 604. 
^[Geol. Survey of Canada, Annual Report, new series, vol. iv, pp. 
36-42 E. 
