The Dartmouth Beds of Bigbury Bay, south Devon

Abstract

The oldest datable Devonian rocks of south Devon are the Dartmouth Beds. They have been examined in the coastal sections between Plymouth and Bigbury Bay and in Slapton (=Start) Bay, where the following successive units are proposed: Warren Sandstones, Yealm Formation, Scobbiscombe Sandstones, and Wembury Siltstones. The Warren Sandstones are similar to the Dittonian rocks of Wales and the Welsh borderlands. The Yealm Formation contains considerable amounts of pyroclastic rocks. The succeeding Scobbiscombe Sandstones occur only at Beacon Point and along the strike inland, and are regarded as a local fluvial grit deposit. Rapidly alternating sandstones and siltstones dominate the Wembury Siltstones succession.