Basin

Basin, in Geology, is a term applied to depressions in the strata, in which beds of a later age have been deposited. Thus, the London basin, consisting of tertiary sands and clays, occupies a hollow in the chalk, which is bounded by the North Downs on the south, and by the chalk-hills of Berks, Wilts, Bucks, and Herts on the north. The term has also been applied to synclinal depressions of strata, as the coal-basin of South Wales. Such synclinal basins do not necessarily give rise to any corresponding depression at the surface of the ground. See ANTICLINE.