Bridport Sand Formation
| Bridport Sand Formation | |
|---|---|
| Stratigraphic range: | |
Cliffs of Bridport Sand between Bridport and Burton Bradstock | |
| Type | Geological formation |
| Unit of | Lias Group |
| Sub-units | Down Cliff Clay Member |
| Underlies | Inferior Oolite Group |
| Overlies | Beacon Limestone Formation or Whitby Mudstone Formation |
| Area | Wessex Basin, Worcester Basin |
| Thickness | Approx. 120 m |
| Lithology | |
| Primary | Sand, Silt Sandstone |
| Other | Clay |
| Location | |
| Country | England |
| Type section | |
| Named for | Bridport |
The Bridport Sand Formation is a sandstone geological formation in central and southern England, noted for forming distinctive cliffs on the Jurassic Coast World Heritage Site. Bridport Sand is of Toarcian (Early Jurassic) age and is found in the Worcester and Wessex Basins.
The sandstone is very-fine grained to fine-grained and contains regular narrow bands that are calcite-cemented and more resistant to weathering, giving it a characteristic banded appearance at outcrop, such as in the cliffs between West Bay and Burton Bradstock in Dorset. It is named for Bridport and has previously been known as the Midford Sand(s), Cotteswold Sands, Yeovil Sands and Upper Lias Sand(s). It forms a locally important aquifer, particularly around Yeovil. It forms one of the reservoir units in the Wytch Farm oilfield in Dorset.