Aust Cliff (SSSI)
Location and Access Information
Grid Reference: ST 565895
Beds and veins of white
gypsum in red marls.
This cliff section on the Severn Estuary is located north of Bristol almost beneath the Severn Bridge landfall at Aust. The section can be accessed via the shore from the hamlet of Old Passage which is accessible via the minor road off the A403. Parking is available along the road in Old Passage.
View the site map on Nature on the Map
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Geological Interest
Aust cliff is a classic geological locality, providing one of the best site exposures in the country of uppermost Triassic and Lower Jurassic rocks, which were deposited approximately 210 million years ago. The exposed rocks show the transition from the desert plain and salt lake deposits of the Mercia Mudstone to the shallow marine and lagoon sediments of the overlying Penarth Group; the sequence documenting the incoming of the Jurassic sea. Of particular importance at this site is the well-known Westbury Bone Bed, a thin bed of rock packed with the remains of fish and bones of marine reptiles, pterosaurs and occasional dinosaurs. The lagoonal deposits of the Cotham Beds at Aust have also yielded an important fossil insect fauna including some specimens with their original colour banding.
