G. F. Monckton — Hwman Skeleton, B. Colwmbia. 369 



eastward about 3 miles up the lake, where the water is shallow, 

 except where there is a current which must have been stronger in 

 the past. There would be found further up the Deadman where the 

 stream was more rapid a development of gravel, which is the case, 

 and as the river built up its delta and the glaciers receded, the silts 

 would be laid down farther back on a higher level, as may be seen 

 now near Criss Creek. There would be a small local development 

 of silts at the mouth of Copper Creek at points where there would be 

 but little current, and a large area at the mouth of the Cherry Creek 

 valley and also at the Tranquille River, where there are actually 

 large exposures of the silts at the mouth and contemporaneous gravels 

 higher up (see Dawson's Report, vol. vii, Geol. Survey, as to this last). 

 If this theory be adopted, and it has always seemed to me the correct 

 one, it would explain why some 10 miles of this lake average over 

 400 feet below the present outlet, which outlet itself is not more 

 than 20 feet above bed-rock showing now in the river below. The 

 only other possible explanation of this hole it that it was excavated 

 by ice, but if so, why did the ice leave the silts untouched at the 

 lower end of the lake ? and there is no trace of such ice. Shuswap 

 Lake to the eastward has the same peculiarity, namely, a rock basin 

 with deltas of silt and gravel close to it, showing no silt along its 

 sides except where it might be locally derived. Should this surmise 

 be correct, another 3,000 years might well be taken off the 12,100, 

 leaving only 9,100 years. 



To my estimates it will no doubt be objected that they are based 

 on too high estimates of glacier work. It is true that researches 

 such as those of Dolfus Ausset on the Unter Aar Glacier premise 

 a much slower rate of glacial deposit and erosion, but against this 

 there are several arguments. The first is that his observations were 

 drawn from glaciers descending from mountain peaks. Now, the 

 fundamental reason for the existence of a mountain peak is that it is 

 composed of the hardest material in the district. Therefore an^ 

 estimate of erosion based upon work done under such conditions is 

 certain to be very low, much too low for calculation of the work 

 done by an ice-sheet crossing all kinds of rock-formations. Then, 

 again, to estimate the work of ice-sheets covering hundreds and 

 thousands of square miles by that which is done by glaciers of such 

 limited area is very deceptive. Therefore I put aside his calculation 

 of 0'6 of a millimetre eroded yearly by the Unter Aar Glacier as 

 useless for our purpose. 



"When we compare the movement of the little glaciers of the Alps 

 with that of the great ones of Greenland we find that while those of 

 Switzerland move at the rate of 3 feet daily, that of Jacobshavn 

 Fiord, 2^ miles wide, moves 60 feet a day according to Helland, and 

 Rink estimated the movement of the Karajek Glacier, 4 miles wide, 

 at 22 to 38 feet daily, and that of others at 24 and 46 feet daily, 

 although he considered that the average motion of glaciers in Greenland 

 was not over 21 feet. 



As to the amount of deposition, Helland repoi'ted a great variation 

 in Greenland in the amount of glacial mud carried down in suspension 

 by glacial rivers, ranging from 2,374 grammes per cubic metre of 



DECADE V. — VOL. X. — NO. VHI. 24 



