508 DET Vi OOKIVATG, OF iG) OE OG Ve 
twenty to thirty miles east of the Rocky Mountains, where, if 
anywhere, the highest margin of the glacial deposits should be 
marked either by moraines or by beach-lines. 
In the course of a much closer examination of these hills than 
had previously been possible, it was in effect found, that they 
show a series of terraces, running up from about 3200 feet to a 
maximum height of 5300 feet above sea level, and that drift from 
the Laurentian Plateau, on the east and the Rocky Mountains 
on the west occurs, as well-rolled shingle, up to the highest level 
of these terraces and no further. The elevation is nearly three 
times that of the Laurentian Plateau, and the circumstances show 
that the Laurentian and Rocky Mountain stones reached these 
high levels at the same time. 
A comparison of the highest levels of the drift in several 
places in southwestern Alberta, indicates the existence of a tract 
of greatest depression and of subsequent maximum elevation in 
a part of that district, and probably that of a series of nearly 
parallel isobases of decreasing amount to the northeastward of 
this tract, trending east-southeast by west-northwest, but turning 
to a northwesterly direction (corresponding with that of the 
mountains) further to the northward. 
Whether the upper limits of glacial deposits be accepted as 
the shore-lines of an extended body of water, as marking the sur- 
face level of a mer de glace or as the margin of a glacier-dammed 
lake, enormous changes of level in the region must equally be 
admitted. 
A search for eastern erratics upon higher parts of the foot- 
hills, in certain localities somewhat extends the spread of this 
drift to the westward, beyond the line drawn for it by me upon 
previous maps. These erratics in fact become quite sporadic in 
their distribution on approaching the mountains. 
Some years ago, while examining the sections of glacial depos- 
its along the Bow Valley, eastward from the mountains, Mr. 
McConnell found reason to believe in the existence of a ‘“‘ western’” 
bowlder-clay which changes gradually to the east into the typi- 
cal Saskatchewan gravels of the plains. This observation has 
