Hornsleasow Quarry

Also within

Gloucestershire County Cotswolds Scenic Area

Condition (Natural England)

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Jurassic · Rock Type: Limestone

Description

Area, 3.5 ha. 9.6 ac. Description This geologically important site exposes a relatively thick sequence of predominantly Bathonian Middle Jurassic oolitic limestones and thin clays of key importance in correlating similar, but thinner, sequences elsewhere in north Gloucestershire. These rocks, belonging to the Clypeus Grit, Chipping Norton Formation including the Hook Norton Member and the Chipping Norton Member, sharps Hill Formation and the Taynton Limestone Formation, are believed to have been laid down approximately 170 million years ago in a warm, shallow sea that covered much of present day Gloucestershire and Oxfordshire. Conditions are believed to have been similar to those which exist today on Bahama Banks in the Caribbean. Evidence for this is provided by the sedimentary structures and the type of fossils found within the rocks. These include well preserved corals, gastropods, bivalves, brachiopods, echinoids and rare specimens of the now extinct ammonites. The latter are of great significance since they enable geologists to date particular rock units and accurately place them within the Jurassic rock succession. Hornsleasow Snowshill Hill Quarry is thus a key site in the reconstruction of an ancient sea that covered much of present day Gloucestershire and Oxfordshire during Middle Jurassic times.