Foss Cross Quarry
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Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| SP055092 | — | Favourable | 0.67 | 2011-08-10 |
Geology & landscape
Mining / Industrial: Quarry · Geological Period: Jurassic · Rock Type: Limestone
Description
Area, 0.67 ha. 1.66 ac. Description Remaining exposures at this former quarry display one of the most important White Limestone Formation Middle Jurassic sections in Gloucestershire. The rocks exposed at this site, predominantly limestones with thin clay bands, have been interpreted as deposits that were laid down approximately 165 million years ago in a warm, shallow sea in conditions similar to those that exist today on the Bahama Banks in the Caribbean. Evidence for this is provided by well developed sedimentary structures and the numerous varieties of fossils, that are found within the rocks. These include forms typical of warm, shallow, seas such as bivalves, brachiopods, corals, gastropods, echinoids and rare specimens of the now extinct ammonites. The latter are of great significance since they have enabled geologists to date certain rock units at Foss Cross and thus place them within the Jurassic rock succession. Also of importance at this site is the occurrence of a red fossil alga Solenopora jurassica, giving rise to the term 'Beetroot Stone' for the uppermost horizons of the section. 'Hardgrounds' areas of hardened sea floor with burrows of rock boring molluscs also occur, indicating an interruption in deposition of sediment on the ancient sea floor. In addition to representing one of the most informative White Limestone Formation sections in Gloucestershire, Foss Cross is also crucial for comparing and contrasting with other similar sections in the area. This has enabled geologists to reconstruct the many environments of the ancient sea that covered much of present day Gloucestershire and Oxfordshire during Middle Jurassic times.