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Proceedings of Royal Society of Edinhurgh. [sess. 
period, would be the ordinary outlet. That the confined waters of 
this lake occasionally burst their ice-barriers is suggested by some 
irregularly deposited debris of aqueous origin observed in the lower 
parts of Glen Spean, If this be an admitted fact, the exceptional 
irregularity of the deposits in question would be readily accounted 
for, as the escaped waters from the Glenroy glacier-lake would be 
sufficient to cause a much greater deluge than anything of the kind 
known in historical times. The descending flood, meeting with no 
lake-basin on the way to act as a temporary stop-gap to its destruc- 
tive course, would re-sort the superflcial deposits in the lower valley 
in such a way as to defy interpretation by the most skilled geologist, 
unless he were conversant with the exceptional glacial phenomena 
here faintly portrayed. 
