the base of a hill, after a severe rainfall, their whole course 

 lined with deep potholes formed by the rush of water and the 

 whirl of the till boulders. The load of detritus spread in a 

 huge alluvial fan at its base, will in many cases measure twenty 

 cubic yards. When the hill slopes to the lake shore, this 

 eroded material, it will be seen, determines the soil content of 

 the beach, especially where there is no intervention of bottom 

 or marsh. The small amount of clay in the till, owing to its 

 very light nature, is carried away in suspension. 



It has been suggested that the stretches of sandy beach 

 of to-day might be accounted for by the combined forces of 

 wind and wave action, grinding up the glacial pebbles and 

 spreading out the accumulation to form the beach. The occur- 

 rence of some of these sand beaches on the north-eastern 

 shores, where the south-west winds for most of the year spend 

 their force, might seem to partially corroborate this, but surely 

 a second thought would dispel it. In the first place no glacial 

 pebbles (quartz pebbles) are exposed to the action of the 

 waves, the accumulation of peat and marl completely covering 

 so heavy and immovable thing as a pebble. The light shifting 

 sands consequent on the side-wash and erosion of the adjacent 

 hills keep the marl and peat deposits well under cover in their 

 immediateneighborhood. In the second case, long stretches of 

 sand beach occur on the southern and eastern shores, where 

 the prevailing winds do not cause the waves to beat. There 

 has been someconfusion in passing judgment on this point. A 

 'beach on this lake, and the other lakes of the neighborhood, 

 is either sand or marl, and it should be easy to determine 

 which. It should be easy to distinguish between a beach 

 made up of fragments and particles of shell-life which is 

 largely calcium carbonate and one made up of sand and gravel 

 mainly the oxide of silica. It is clear then, that the origin of 

 these sand beaches is connected with their closeness to the 

 sand and gravel hills and ridges, the change in place being 

 effected by erosion and side-wash, and not in grinding and pil- 

 ing up by wave and wind action of glacial pebbles.' A casual 

 inspection of the map of contours should show this. 



The stretches ot marl beach are in part one of the present 

 enigmas to be cleared. They seem, on close inspection, to 



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