On the Pleistocene Flora of Canada
I. GEOLOGY OF THE DEPOSITS. BY SIR WM. DAWSON. General Geology of the Pleistocene The Pleistocene deposits of Canada may be defined as consisting of three principal members, which may be characterized as follows, in ascending order: 1. The Till, or lower bowlder clay, a tough or sometimes sandy clay, containing local and traveled stones and bowlders, often glaciated. It usually rests on glaciated surfaces, but is sometimes underlain by stratified gravels or by old soil surfaces or peaty beds. These are, however, rare and local.* In the more maritime regions— e. g ., in the lower St. Lawrence—it contains marine shells of arctic species. Farther inland— e. g ., in western Ontario and in the plains west of Red river—it is not known to hold marine remains. 2. Stratified clays and sandy clays. In the more maritime regions these are the lower and upper Leda clays, holding many marine . . .