Crookhill Brick Pit, Chickerell SY 644 798
This disused brickpit is a Site of Special Scientific Interest (SSSI) and Geological Conservation Review (GCR) site. It provides the best exposure of Lower and Middle Oxford Clay in southern England, showing a sequence through the Jason, Coronatum and Athleta Zones, of Middle Jurassic age.
There are considerable differences in zonal thickness and lithology between this section and the sections in the Midlands, with the Grossouvrei Subzone being greatly expanded at Crookhill. The clays and shales seen here contain a rich fauna of ammonites, belemnites and bivalves, with the Athleta Zone fauna being particularly prolific and important. Reineckeid ammonites, usually rare in the British Callovian, occur fairly commonly in the Athleta Zone here.
Crookhill is a key locality for British Callovian biostratigraphy.
It is also a nationally important site because it supports an exceptional population of great crested newts Triturus cristatus. The SSSI includes the breeding ponds and the terrestrial habitat that is used by the newts for resting, foraging and hibernation.
Crookhill Brick Pit is located three kilometres to the west of Weymouth. The site is situated on Oxford Clay.