406 Proceedings of the Royal Society 
If difficulty be still felt in regard to the amount of water required 
for those old floods, we might appeal to the kind of proof by which 
the existence of a former glacial epocli in Scotland is established. 
Who that looked to the present ice and snow of a Scottish winter, 
could think it likely that glaciers once filled the valleys of the 
Pentlands, and that masses of moving ice rose over the flanks of 
Arthur’s Seat. We point to the rounded and striated rocks, and 
say, there are the foot-prints of the old glacier,—and the thing is 
proved, no matter how different may be the cold of our present 
winters. And why not reason thus in regard to the old floods ? 
Who that looks on the present flow of our streams could realise 
floods able to raise those old 80 feet terraces ? But why should 
we not point to these deposits where they lie, and say, these strati¬ 
fied gravels and bedded sands are the workmanship of the old cur¬ 
rents, which once swept and eddied at that height down these 
valleys. If this kind of evidence makes you believe in the great 
old glacier all unlike our present ice, why should not similar proof 
make you believe in the great old floods of a former epoch, all 
unlike though they may be to our present streams ? 
And yet in Strathspey, with the traces of the Moray floods all 
around us, it is easier to believe these things than it would be 
almost anywhere else. It was at Coulnakyle, the scene of one of 
these drawings, that Captain M‘Donald, B.N., a sailor of the old 
school, looked out and saw the Spey, about a mile wide, covered 
with waves, that put him in mind of Spithead in a fresh gale 3 and 
felt sure, as he told Sir T. D. Lauder, that he could have sailed a 
fifty-gun ship from Boat of G-arten to Bellifurth,a distance of seven 
miles. The small burn of Drumlochan, which in its ordinary state 
“ is hardly sufficient to keep the saw-mill going,” rose till it swept 
away two bridges of twenty feet span, the column of water being 
estimated at 400 square feet sectional area. As the miller of Dal- 
nabo expressed it, u the height the burns rose to that day w r as just 
a’ thegither ridiculous.” In looking back to the time of these old 
deposits, it is generally admitted that the volume of the rivers was 
decidedly greater than it is now. Mr Prestwich, as we have seen, 
assumes that the old Somme was five times the present. If we 
might suppose something like this in the Spey—if, further, there 
was along the valley an amount of alluvium sufficient to confine 
