Abstract

1. Introduction.—If we separate the southern counties from the rest of England by a line following up the Thames to near Cirencester, then along the southern boundary of Gloucestershire to the Severn at the mouth of the Avon, we get an irregular strip of country, shaped somewhat like a fish, of which Kent forms the head, and Cornwall the tail. Excepting, perhaps, some of the hills of Somersetshire, this part of England appears to have been entirely free from the action of land-ice in the Glacial period; and there are no glaciated rock-surfaces, no true till, and no moraines. Along with, and, as I believe, in consequence of, this freedom from ice-action, there is also an utter absence of those fragmentary marine shells which, further north, are found in drift on both the eastern and western coasts, where the great streams of ice from the north, after crossing arms or channels of the sea, advanced upon the land—and the presence of which, as they are never found above heights to which the circumpolar ice reached, and for other reasons I have urged, is due, not to the submergence of the land beneath the ocean, but to portions of the ocean-bed having been carried up by the rising ice*.

The purpose of the present paper is to describe the surface-geology of the counties of Devon and Cornwall, to examine the theories that have been proposed to account for the origin of the drift beds, to give my own views on the