Pitstone Quarry SSSI

Bucks County Council administration area: Aylesbury Vale District Council; Buckinghamshire County Council.

Grid reference: SP 934 145

Area of site: 10.3 ha, 25.4 acres

Access, location and parking: Good parking at the College Lake Nature Reserve (pay for permit to park and enter site). Gates are open from 10 am until 4 to 5.30 pm dependant on time of year. Groups possible with coach parking possible.

Site description: Also known as College Lake and it is a nature reserve and conservation area for public use. Entrance to the site is located close to Bulbourne. The section notified for SSSI coverage is the area of the Middle and Upper Pleistocene deposits – the grid reference given is that of the ‘channel’ location.

Geological interpretation: The disused quarry was used to extract Lower to Middle Chalk for the cement industry. The Lower Chalk is now mostly flooded as the old workings have become the area of a deep lake and shallow water wetland area for nature. However, the far slopes do show the Middle Chalk, although gradually becoming less exposed due to slope degradation and plant colonization.

There are good examples of Chiltern dipslope deposits all over the site, of Middle to Upper Pleistocene age. Slope processes, such as solifluction are visible in several areas. A number of channels occur in the slope deposits, which were infilled with water-lain deposits. Three channels yielded significant faunal and floral assemblages and showed they were of different ages. The oldest is claimed to be a new interglacial period occurring between the Hoxnian and the Ipswichian interglacials. It lies stratigraphically below the second channel deposit which contains hippopotamus bones and is thought to represent the Ipswichian interglacial (the last interglacial). The evaluation of these various channel-fills and their stratigraphic relationship continues, making this an important stratigraphic site for the Pleistocene.

Current and potential educational  use (geology, ecology, archaeology, industrial archaeology): The site is of excellent value for education, although the channel locality is not open for viewing. There is a display of fossils and reconstructions on site and other geology to view.

Conservation interest: To maintain the integrity of all the potential geological resources.

Threats to site (present and future): None envisaged as it forms part of a nature conservation area.

Constraints (basic risk assessment): usual risks for open public access nature site.

Development potential: This site could make an excellent RIGS site. The RIGS coverage is for the geology of the remaining site, not that already protected under the SSSI notification.

Reference list/bibliography:

Recommendations: Develop the interpretation of the chalk geology and slope deposits for public enjoyment, other than the ‘channel’ area which is under SSSI protection.