The structure of Gower

I. Introduction The peninsula of Gower, extending 16 miles westwards between Swansea and Carmarthen bays, is a remnant of the Armorican fold system that at one time formed continuous mountain ranges—the front of Meso-Europe—along the southern borders of Wales. Its coastal outline and trend are a reflection of the earth-movements its rocks have suffered, while its inland topography is also largely determined by the strike of the rock outcrops. Apart from insignificant Triassic outliers in the south-west of the peninsula, the solid geology is wholly Upper Palaeozoic. Coal Measures crop out along its north-eastern border and in the coalfield to the north, but are elsewhere absent. The greater part of the peninsula is a plateau of Carboniferous Limestone, complexly folded, in which synclines of Millstone Grit shales form embayments and depressions at Oystermouth, Oxwich, and Port Eynon, and above which the anticlinal cores are marked by the monadnock hills of Old Red Sandstone—Cefn Bryn and the western downs. The general geology is illustrated on the maps of the Geological Survey (New Series 1-inch maps nos. 246, 247) and is described in the accompanying memoirs (Strahan and others 1907a, 1907b). Following the early work of de la Beche, the Survey officers clearly distinguished the various rock types, and determined the nature of the major structures so far as this was possible by a close examination of dip and strike, and of lithology. At a later date Dixon and Vaughan (1911, p. 479) indicated the location of some of the zones in