On some Submerged Rock-valleys in South Wales, Devon, and Cornwall

Abstract

The following particulars of some rock-valleys below the sea-level were for the most part gathered by me in former years, during the execution or the projection of engineering works with which I was more or less connected, or well acquainted. Information has also been afforded me from time to time by the courtesy of the engineers of other works in which similar sections have been exposed. The main object in the present paper is to put the facts observed on record in a connected form. The details of the sections now given are, from a geological point of view, more incomplete than could be wished, as must almost always be the case when observations are made during the progress of engineering works by those to whom they are not matters of primary importance. Things observed are not always recorded, or perhaps their significance is not understood until they are lost to view. Notes and sections, when made, are lost sight of, or are laid aside for further information or a more convenient season, which, as in the case of some of these sections, may be a long time in coming. The localities naturally fall into two groups:—(1) on the southern coast of Wales, from Milford Haven to the Severn; and (2) on the southern coast of Devon and Cornwall, from Dartmouth to Falmouth. I. S outh W ales . Milford Haven. This estuary extends 20 miles inland, with two main branches, which are fed by streams rising on the Presee]ly Hills (]760 feet)