CYNGOR CEFN GWLAD CYMRU

COUNTRYSIDE COUNCIL FOR WALES

SITE OF SPECIAL SCIENTIFIC INTEREST CITATION

VALE OF GLAMORGAN HAYES POINT TO BENDRICK ROCK

Date of Notification: 1986

National Grid Reference: ST 138671

O.S. Maps: 1:50,000 Sheet number: 171

1:25,000 Sheet number: ST 16

Site Area: 29.5 ha

Description:

This 1.8 km stretch of coastline lies to the south east of Barry on the northern shore of the Bristol Channel. The whole length of the cliffline and foreshore provides excellent exposures through important rock sections of Triassic age while the vicinity of Bendrick Rock is one of the best localities in Britain for fossil footprints.

The Hayes Point to Bendrick Rock coastal section provides excellent exposure of Triassic lake and river deposits. Fine-grained, lake-margin sediments occur here, interbedded with coarse-grained fluviatile (river) sediments, representing the marginal facies of the Triassic Mercian Mudstone Group of South Wales. The finer sediments include siltstones with nodular evaporites, wave-rippled siltstones and fine sandstones, and thin graded sandstones of sheet-flood origin. The coarse fluvial sediments include a limestone conglomerate up to two metres thick, together with occasional thin, matrix-supported conglomerates, interpreted as the products of debris flows. Sediment transport was towards the east and south west. This is a key locality for the interpretation of Triassic lake and river environments.

Bendrick Rock is one of Britain's best localities for fossil footprints and the best for such trace-fossils in rocks of Triassic age. Dinosaur trackways have been known from South Glamorgan for over 100 years, and were first described by Sollas under the name of Brontozoum thomasi. Latterly the specimens from this new site have been attributed to the ichnogenus Anchisauripus, a form name normally associated with bipedal prosauroped dinosaurs.