MODERN ACTION OF RIVERS. 
375 
Action of freezing water in deepening river channels. 
The manner in which streams deepen their channels, particularly in the rocks of the southern 
counties, is illustrated at every step. The rocks, consisting of alternations of hard and soft 
materials, are readily influenced by the freezing of water; and the bed of any stream can 
scarcely be examined, but the strata will be found elevated in the centre, and dipping toward 
each side. Sometimes the elevation is on one side, and the dip towards the other. This 
takes place by the water first finding its way through a fissure beneath the stratum, where it 
freezes and elevates the rock; loose earth and pebbles find their way into this enlarged fis¬ 
sure, and beneath the stratum; during the succeeding winter, a larger quantity of water 
freezes beneath it, and elevates it still more. If the breaking up in spring does not remove 
it, the next winter will be sufficient, and then the whole is carried onward, with ice, stumps, 
trunks of trees, etc., till it finds some level place in the bed of the stream, where the whole 
rests for a period, to have the same operations renewed. 
The following illustration is a sketch from the bed of the south branch of the Cattaraugus 
creek. A thick stratum has been elevated by the freezing of the water, till its edges are above 
the surface. This sketch was taken two years since, and probably the whole is now replaced 
by others. 
180 . 
This mode of operation is constant; and no sooner is one portion removed, than another is 
lifted up, to follow in the same manner. In the thick-bedded limestones, its effects are less 
rapid; but even here the influence is perceptible, and occasionally large blocks are loosened 
and carried down the stream. 
