Valley
in geology, a long depression or hollow on the surface of the earth, margined by ground more or less high. It may be on a vast scale of magnitude, as the bed of an ocean would be if upheaved sufficiently to become land, or it may be comparatively small but broad; or narrow, as a glen or a deep gorge, called by Americans a cañon or gulch. It may be surrounded by hills, or may constitute a depression crossing a country from sea to sea.
Valleys of stratification are produced by the decay and removal of shale or other soft rocks, while the less destructible hard rocks remain. Other valleys have been excavated by rivers alone. Many valleys on low-lying plains adjacent to the sea have originally constituted river beds and banks, then through a depression of the land the ocean has gained access to them, constituting them estuaries; then again upheaval has made them land valleys.
Other valleys have constituted the beds of old lakes. Valleys, resembling troughs, on table-lands are in many cases produced by the flexure of strata laterally, so as to constitute a series of ele- Lawrence river and on the Grand Trunk and the St. Lawrence and Adirondack railways; 38 miles from Montreal. Near by is the head of Beauharnois canal, constructed past the rapids of St. Lawrence.
The river here is crossed by a splendid railway bridge. The town contains a cathedral, a number of beautiful public buildings, and the residence of a Roman Catholic bishop. Pop. about 10,000.