The Cefn Bryn Shales of Gower

Abstract

In 1901 (Swansea Memoir, p. 5; West Gower Memoir, p. 4) the Officers of the Geological Survey (R. H. Tiddeman and B. S. N. Wilkinson) discovered olive-coloured shales and mudstones in outcrops on Cefn Bryn, Gower. They considered these strata to be “succeeded naturally by Old Bed Sandstone”, for the larger outcrop is bounded on the south by brown sandstones and quartz conglomerates dipping southwards at about 30 degrees. It was therefore natural that these beds, apparently obviously older than the contiguous Old Red Sandstone, should be referred to the Silurian. Tiddeman obtained fossils from the shales which were identified by E. T. Newton as “Rhynchonella (like R. nucula), Bellerophon (like B. murchisoni), Modiolopsis?, Chonetes sp., crinoid ossicles, and entomostraca”. The evidence of the fossils thus seemed to confirm the conclusions made on the field evidence, though (as shown by the private records of the Geological Survey) Newton was doubtful of the precise age of the fossils and questioned their reference to the Ludlow.