Meeethicj of the American Assoc/afion. — Upham. 225 
delta sand and gravel, usually 10 tii 20 feet deep, a considerable thick- 
ness of stony and gravelly clay or till is passed through, with occasional 
enclosed beds of stratified gravel and sand: but that the lower portion 
of some of the deep drift sections consists chiefly of sand and gravel, 
resembling those of the present lake beaches. In the till of the well at 
the public square he bored through a log fully two feet in diameter, 
thought to be oak, at the depth of 125 feet. In this well a stratum of 
seven feet of very fine quicksand lay immediately upon the shale, at the 
depth of 205 feet from the surface; but in pome other deep wells the 
lowest drift deposit is clay, probably till. 
The deep preglacial valleys of the Cuyahoga and Rocky rivers, tribvi- 
tary to the basin which now holds lake Erie, testify, with many other 
similarly deep and drift-filled preglacial river courses throughout the 
interior of our country, that immediately before the Ice age this conti- 
nent was uplifted much above its present altitude, giving steeper gradi- 
ents and increased poweV of erosion to the streams. The duration of 
the uplift, however, was not geologically long: else the narrow gorge of 
the Cuyahoga would have become a wide valley, and, on the borders of 
the continental plateau, the fjordlike ccmtinuation of the Hudson and 
other rivers, and the northern and Arctic fjords, would have Vjeen wid- 
ened to mature valleys, with extensive lowland plains and gently sloj)- 
ing sides. 
Such great depth of erosion by the preglacial Cuyahoga river shows 
that the Tertiary and Quaternary river of the lake Erie basin had its 
course on a land surface which is now covered and raised, probably for 
the greater part from 200 to 400 feet, by the deposition of glacial and 
modified drift during the Ice age. The topographic irregularities of 
the preglacial Erie valley are thus largely enveloped by the drift, which 
forms a very level expanse beneath the shallow lake. The Vjeds of coarse 
gravel contained in the till near its base, as in the Standard Oil Com- 
pany's well, indicate fluctuations of the glaciation in its early stages, 
with free drainage conditions, the altitude being greater than now, and 
the lake area not yet depressed to be a closed basin. 
15. A Reviaioa of tfie Moraines of Minneaota. J. E. Todd. This 
paper presented first a map of the moraines of northern Minnesota as 
interpreted and mapped by Mr. Upham in the Twenty-second Annual 
Report of the Minnesota Geological Survey, in which the northern mo- 
raines, in the series of twelve found in this state, are represented as ex- 
tending in general from east to west across that district, having been 
formed successively during a motion of the ice-sheet principally from 
the north. The following objections were urged against this interpre- 
tation. 
1. It,a8sumes that latitude had more to do with the ice movement 
than altitude, and that topography had little efl'ect on the movements 
of the ice-sheet. On the contrary, in the case of the present glaciers of 
Alaska and (Treenland, as well as of the Dakota, Iowa, and Wisconsin 
loVjes of the ancient ice-sheet, it apj)ears that, at least in the zone of 
ablation, glacier lobes, like streams, flow farthest in the valleys. It 
