Seismic Prospecting in the Western Approaches of the English Channel

Summary On the basis of the measured seismic velocities, the layering found at 25 seismic stations in the area of the Western Approaches of the English Channel is divided into four classes which are respectively correlated with semi-consolidated Cretaceo-Tertiary sediments, the New Red system, the Palaeozoic system, and a metamorphic basement. The last of these appears to form a long, deep trough. The Palaeozoic floor is depressed in a trough of somewhat variable depth, bounded on the north by an outcrop of the metamorphic basement which is possibly a westward extension of the upthrust Lizard-Start metamorphic belt. Contour maps of the layering are produced.