EROSIONS. 209 



But the power of the atmosphere to produce disintegration Avould be small without the 

 aid of water. This is the grand agent in the work, and without it other agencies would 

 be .comparatively inefficient. Carbonic acid especially becomes very efficient when 

 dissolved in water, which is thus made capable of dissolving nearly every sort of rock. 



Water alone does, indeed, possess the power of dissolving most rocks, though in minute 

 quantity. It is remarkable also for its power of penetrating rocks, not only finding its 

 way into all fissures, but by means of capillary attraction penetrating far into the solid 

 mass, as we have already shown. In this way we often find the rocks to the depth of 

 several feet, so thoroughly disintegrated that currents of water, and especially if loaded 

 with ice, will sweep off the loosened mass and thus prepare a new surface to be acted 

 upon by the water, or even the vapors of the atmosphere. 



The power of water in the frozen state as glaciers, icebergs and icefloes is very great: 

 but still greater when it exerts its expansive force in freezing. Gunpowder hardly equals 

 it ; and probably a large part of the loose materials scattered over the surface as bowlders, 

 are first loosened from the ledges by the freezing of water in the crevices of the ledges. 

 Even though they get only an infinitesimal start the first year, each subsequent year 

 because the crevices are widening will witness an increase of the work. 



By these various agents have the materials been got into readiness to be transported 

 to their present situations, chiefly by the ocean and rivers. The greatest part of the work 

 has probably been done by the waves, tides, currents and icefloes of the ocean, as the 

 land has sunk and risen again and again, thus making every foot of its surface repeatedly 

 and for long periods the shore of the ocean. The drainage of the land, also, by rivers, 

 accomplished again and again by these vertical movements, has worn out gorges and 

 valleys of great depth, and the work has not yet ceased. Several of the agencies have 

 often acted together, and we are rarely able to say how much has been done by each. 

 The effects which they have produced in Vermont, singly or conjointly, we shall now 

 attempt to show by examples. 



THE GORGE AT BELLOWS FALLS. 



On the east side of Connecticut River at Bellows Falls, Kilburn Peak rises very precip- 

 itously 828 feet above the river at the top of the falls, and crowds close upon it ; while on 

 the west side, the country rises rapidly towards the Green Mountains, to a still greater 

 height. One can hardly look at the narrow passage of the river through this gorge, 

 without awakening the inquiry whether it has not been worn out by the river, or some 

 other agency. If so, the valley above the spot must once have formed a lake, which, 

 according to the present levels, would be 800 feet deep. Starting with Kilburn Peak and 

 going northeasterly, we shall find the watershed between the Connecticut and Merrimac 

 valleys extending almost in a strait line to Franconia, and then turning more to the right 

 to Mount Washington. The lowest point in this ridge south of the White Mountains 

 is on the Northern Railroad from Concord to Lebanon, in Union, where it is 682 feet 

 above Connecticut River at Lebanon, and 822 feet above the river at Bellows Falls. On 

 the Vermont side of the river the country rises to the Green Mountain ridge, and the 

 lowest depression in it south of the latitude of the White Mountains, is on the Vermont 

 Central Railroad at Roxbury, which is 930 feet above the river at Lebanon ; the lowest 



