Some Effects of Ice Action near Grand Lake, Cape 

 Breton. — By W. S. Brodie, B. A. 



Read 24th April, 1909. 



In the vicinity of Grand lake, about four miles from Syd- 

 ney, as also near other lakes within a radius of fifteen miles 

 from that spot, may be noticed some curious formations. 



Roughly parallelling the shores of Grand, Waterford and 

 Sand lakes are found mounds of considerable extent. These 

 mounds vary in length, height, and width, running through 

 swamp, forest and open ground. Sometimes they leave the lake 

 ehore distant hundreds of yards, at other places sloping to the 

 water's edge. To consider the nature and origin of these 

 mounds is the object of this paper. I will refer particularly to 

 that at Grand Lake as being a type of all. 



Size. — In length, I have traced this one in a fairly continu- 

 ous line, though with frequent breaks, for over a mile. 



Height. — Five or six feet above present lake level is their 

 limit. Above the ground at base, the extreme height is about 

 4^ feet. The elevation of crest seems to bear no uniform ratio 

 to distance from ])resent shore line. I had no means of taking 

 levels along the summit, but judging by the eye it is nearly 

 level. There is at least no decided slope in either direction. 



Width. — Where the mound is most pronounced, I found its 

 base to measure about 15 feet in cross-section, its top about six. 

 Allowing a height of five feet, this gives a side slope of 1 in 1.3. 

 Generally, the slope is much less decided. I would judge that 

 when first deposited the slope was sharp. Weathering, erosion, 

 and plant growth has evidently flattened it to a large degree. 

 I could not determine whether the side slopes differed in any 

 uniform way on the same mound. Sometimes one side, some- 



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