236 FORCE OF LARGE MASSES OF WATER SET IN MOTION. 
lake, we could scarcely believe that there are valleys of many miles 
in breadth, and many hundred feet in depth, which owe their origin 
exclusively to the excavating power of a flood of waters. 
Our present rivers excavate but little, as they flow through 
valleys already formed by an overwhelming ocean ; and the de¬ 
structive action of the present sea is limited to the partial cutting 
away of cliffs by the slow undermining of the waves in storms and at 
high tides. Yet we know from the effect of a mountain torrent 
in cutting ravines and drifting gravel; from the blocks of granite 
which were lifted to an elevated point on the side of a mountain by 
the bursting of a small lake in the Val de Bagnes, in Switzerland, 
a few years ago; and from the excavation of the Zuyderzee, by the 
bursting of a dyke in Holland; that the force of water in rapid 
motion is competent both to transport such masses of gravel and 
granite blocks as we have been tracing over the world, and to ex¬ 
cavate valleys which though many miles in breadth, and many hun¬ 
dred feet in depth, still bear a due proportion to the bulk and power 
of the agent that produced them. 
“ When we call to mind,” says Mr. Sumner, in his inestimable 
and most judicious work on the Records of Creation, Vol. II. p. 350, 
“ the destruction which is spread by a sudden alteration in the level 
of a very inconsiderable body of water, even to the extent of 50 or 
100 feet, we cannot easily assign limits to the effect of a body of 
waters like the ocean pouring in over the land when its level was 
destroyed; we are at a loss to conceive what the power of such a 
machine might be when once in operation.” 
An agent thus gigantic appears to have operated universally on 
the surface of our planet, at the period of the deluge ; the spaces 
