Barnhill Quarry
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Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| ST725827 | — | Favourable | 2.92 | 2021-11-16 |
Geology & landscape
Geological Feature: Karst, Rock Outcrop · Mining / Industrial: Quarry · Geological Period: Carboniferous · Rock Type: Carboniferous Limestone, Limestone, Sandstone, Shale
Landscape processes: Karst
Description
Area, 3.1 ha. 7.7 ac. Description The Carboniferous Limestone exposed here spans the Arundian and Holkerian stages of the Visean Series. The section shows the Lower Cromhall Sandstone and Clifton Down Limestone in extensive exposures, which are particularly good for the demonstration of sedimentary structures. The shallow marine and peritidal limestones of the Clifton Down sequence, which include coral beds and stromatolite horizons, have received detailed study and environmental interpretation. This is an important site for studying and demonstrating the sediments and facies of the Visean limestones in the northern part of the Carboniferous Limestone outcrop. A 'Rhaetic' section here lies above a spectacularly planed surface of Carboniferous Limestone. The planed edge of the upturned Carboniferous shows karstic grikes where the 'Rhaetic' has been removed by quarrying. Above a Westbury Cotham section is exposed, to a thickness of six metres. This includes a basal 'bone bed' which takes the form of a pebble bed containing vertebrae and teeth. A normal bivalve and fish fauna is richly represented in the overlying shale sequence.