Having been for the last twelve months engaged in a careful study of the post-Tertiary geology of the eastern part of Shrop-shire, I have at length arrived at the conclusion that the denudation of the New Red Sandstone in this neighbourhood, and consequent excavation of the Tern basin, has been effected partly by glacial and partly by marine agency; the grounds upon which this conclusion is based being:—(1) An attentive consideration of the general form and outline of the basin; (2) A particular examination of the drift beds contained therein.