Abstract

Introduction.—Singularly enough, as geologists approach our own era the difficulty of determining the relative age of a particular stratum generally increases; and it is in the more modern tertiaries, or deposits succeeding to these, that the greatest amount of difficulty occurs. Among the strata not yet referred to any certain epoch, but broadly designated “tertiary,” are the clay-, sand- and lignite-beds, known to geologists as the “Bovey deposit.” Having been for the last ten years engaged in working and boring the various beds of clay, I may have become possessed of facts not generally known to geologists, bearing on the origin and nature of the deposit, and which may assist in some degree to fix its relative age.

The Thysical features of the basin.—The Bovey basin is a depression beneath the level of the surrounding country; its length, from Bovey-Tracey to about two miles south of Kingskerswell, is about 10 miles; its breadth at the upper end about miles, becoming miles, becoming much narrower towards its southern extremity. Two rivers, the Teign and the Bovey, both having their sources in the granite of Dartmoor, run into this basin, meet above Stover, and fall into the sea at Teignmouth. The Teign, the larger and more circuitous, for about 13 or 14 miles before entering the Bovey basin, flows through the slate ; and the Bovey River, rising near the centre of the moor, crosses for a short distance the slate, and rims into the