Aust Cliff

Also within

Gloucestershire County

Condition (Natural England)

Climate exposure

This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.

Geology & landscape

Geological Period: Carboniferous, Triassic · Rock Type: Carboniferous Limestone, Limestone

Landscape processes: Coastal

Description

Area, 5.3 hectares 13.1 ac Description , 1. Rhaetian A classic site showing 'Keuper', 'Rhaetic' and lower Lias unconformably overlying Carboniferous Limestone. The Rhaetian section of Westbury and Cotham Beds the White Lias is absent particularly the basal Westbury Bone Bed, has received much attention from geologists. This conglomeratic unit contains rich fish faunas, marine reptiles and the dinosaur Avalonia. The Cotham Beds contain a 'landscape marble' development and an insect bearing Eustheria bed, above a comparatively thin development of the Westbury Beds. 2. Permo Trias This thick section provides one of the most important Triassic exposures in the country; showing the transition from the red 'Keuper Marl' through the 'Tea Green Marls' Blue Anchor Formation to the overlying Rhaetic Beds Penarth Group. The red mudstones of the 'Keuper Marl' include massive nodular gypsum and show a sharp transition to the overlying green mudstones and sandstones of the Blue Anchor Formation. 3. Palaeoentomology This is the most productive locality in Britain for Triassic insects. Several species new to science have been described from here and others are currently being studied. Thes pecimens occur mainly in blocks of Rhaetian limestone from the top of the section. Fossils tend to occur in rare concentrates and the fauna includes a high proportion of complete bodies. Members of the Mecoptera are particularly common, some species having the colour pattern preserved. A nationally important palaeoentomology locality. 4. Vertebrate Palaeontology Aust Cliff is famous for its 'Rhaetic bone bed'. This has been the source of much vertebrate material, which makes this locality the best site for Triassic marine reptiles in Britain. Hundreds of bones have been collected over the past one hundred and fifty years, including specimens of icthyosaurs, plesiosaurs as many as four species,'dinosaurs' and possibly pterosaurs as well as other as yet unidentified forms. Aust is internationally significant for the reptiles from its bone bed.

Species mentioned