Hinton Hill, Wellow

Also within

Somerset County Cotswolds Scenic Area

Condition (Natural England)

Geology & landscape

Geological Period: Jurassic · Rock Type: Limestone

Description

Description The Twinhoe Ironshot facies of the Twinhoe Beds is a very localised development of limestone with ferruginous ooliths within the great Oolite succession of the Peasedown St John Wellow Hinton Charterhouse area, near Bath. This distinctive unit yields a varied bivalve brachiopod fauna but most importantly is noted for the occurrence of ammonites of the Orbis Zone of the Upper Bathonian. This fauna is virtually unknown elsewhere in Britain and is therefore of great importance for accurate international correlations with areas where a similar fauna are well documented e.g. southern Germany. Ammonite faunas of the Twinhoe Ironshot include Oxycerites orbis Giebel, both macro and microconch forms, Proceritestwinhoensis Arkell including the type specimen and Homeoplanulites sp. all forms of significant correlative importance. The best surviving sections of the Twinhoe Ironshot facies are in a shallow cutting on Hinton Hill, where over 1.5 metres of the facies overlies Combe Down Oolite. The site is of great importance, not only to studies of the stratigraphy of the Middle Jurassic of the Bath district, but also to the British Bathonian as a whole. No other deposit in Britain yields a representative ammonite fauna of the Orbis Zone a key stratigraphical marker in the Upper Bathonian of Europe and historically the Twinhoe Ironshot contributed to the first ever descriptions of the zone as a stratigraphically distinguishable unit.