April, 1902.] 
A Possible Cause of Osars. 
257 
A POSSIBLE CAUSE OF OSARS. 
Geo. H. Coeton. 
On the 20th of April, igor, there fell in north-eastern Ohio an 
unusually heavy snow covering the ground to a depth of from 
twenty inches on a level to seven feet in drifts. The snow came 
very rapidly and went very rapidly. During the period of rapid 
melting strong currents of water flowed beneath the snow which 
in some cases carried along much sediment. It was my good 
fortune to observe a point near the borders of a gently sloping 
plowed field where one of these streams, becoming clogged, rose 
to the surface and flowed for a short distance over the dense 
snow, spreading the abundant sediment, which it carried in a 
sinuous belt along its channel. After a time the stream deserted 
this surface channel and found a new one beneath the snow. As 
the snow melted the belt of sediment which had accumulated in 
the channel on its surface gradually settled, and when the snow 
had disappeared it rested upon the turf that bordered the plowed 
field as a minature osar. 
While it is rightly assumed that the surface of the glacial ice- 
sheet was for the most part clean and free from earthy deposits, 
yet near its southern margin there may have been much sediment 
on its surface. Streams of great force and volume, heavily laden 
with glacial detritus, flowed beneath the ice, and it is possible, 
and even probable, that the shifting of the melting ice, under- 
mined by the flowing waters, and the displacement of the loose 
material of the deep moraine as the ice reacted upon it, would 
occasionally clog the channels of these streams and compel them to 
find new ones. In most cases the new courses would be beneath 
the ice as before, but it is reasonable to assume that sometimes 
the obstructed stream, like the rill in the snow-field described 
above, would rise through some crevasse and flow for a time over 
the surface of the ice. Such a stream would have its rapids 
swept clean of sediment, and its stretches of deep and sluggish 
water in which would accumulate belts of sand and gravel. 
When the stream deserted its ice channel, as it surely would in 
time, these sinuous belts of sediment would lie almost undisturbed 
upon the surface of the glacier, and they would be left finally, 
when the ice had disappeared, as ridges over the surface of the 
land, forming what glacialists call osars, or serpent kames. 
Indeed, such surface accumulations would be far less likely to be 
disturbed and obliterated by subsequent changes than would 
those gravel belts which, in spite of the many difficulties involved, 
it has been assumed, might be formed beneath the ice by sub- 
glacial streams. 
Hiram College, Hiram, O. 
