368 0. F. Monckton — Human Skeleton, B. ColuTnhia. 



One-third inch on 500 square miles would fill lower trough of Tears. 

 50 square miles in 1,800 years, and from just below the 

 1,200 ft. level in 1,100 



One-third inch on 500 square miles would fill the middle stage 

 up to the top and provide sufficient for the deposition of silts 

 in all the sheltered bays up to 2,500 feet in . . .7,200 



Total number of years for deposition of silts since burial 



of the skeleton 8,300 



In making this estimate we must remember that the time would 

 probably be much less: (1) because of frequent slides from the 

 mountains, which would till many places with local material; 

 (2) because when the great glacier covered all this region and was 

 travelling over high ridges it would naturally tend to leave deposits 

 of boulder-clay at several j)oints in hollows, or in places where on 

 account of the flattening of the grade it could not exert much pusliing 

 power, and as the glacier retreated these deposits would be very 

 quickly reasserted by the flooding waters. It appears to me that for 

 these reasons the above figures might well be reduced by 1,500 years. 



Without making such an allowance, there would have elapsed ^ ' 



since the burial of the skeleton ...... 8,300 



If we allow 2 feet in ten years as the average rate for the 

 cutting down of the silts when the land began to rise from 

 the 2,500 ft. level to the water-level in Kamloops Lake, the 

 outlet would be reduced to 1,140 feet in less than 6,800 years 

 (high-water mark is 1,138 feet) 6,800 



Total number of years since burial .... 15,100 

 The rate of cutting down would probably be much greater : 

 (a) because silt deposits above 2,000 feet would not be universally 

 distributed ; [b) on account of the rush of water which would follow 

 the removal of dams in the narrow gorge to the west near Spences 

 Bridge ; {c) the uplifting of the land, say 1,000 feet ; (d) the lake has 

 now cut down so low that the grade of the river below it is only 

 10 feet to the mile, and therefore its excavating power is very small 

 now compared to what it must have been. I should make a further 

 deduction of at least 1,500 feet for these reasons. 



The cutting down has not been carried on at an even rate, since it 

 is evident from the appearance of terraces and old shorelines in the 

 valley that the level of the water has at times been almost stationary 

 and at others it has been lowered with a sudden rush, due probably 

 to the breaking of dams and in some part to the elevation of the land. 

 These two deductions would reduce the total to 12,100 years. There 

 is also another possible reduction to be made. These calculations 

 have been founded upon the theory that the whole lower trough of 

 the valley was filled by the silts. There is an argument against this, 

 which is, the peculiarity (referred to by Dr. G. M. Dawson in several 

 papers) that the greater part of Kamloops Lake is evidently a rock 

 basin, 400 to 600 feet deep. If it was once all filled with silts, how 

 could it be excavated? If we assume, however, that the silts were 

 simply deposited in limited areas, each area fed by its own river system, 

 the explanation appears simple. We should then have the silts 

 of the Deadman lliver extending westward from its mouth and 



