South Lodge Pit SSSI

  Bucks County Council administration area: Buckinghamshire County Council; South Bucks District Council.

Grid reference: SU 905 819

Area of site: 0.53 ha; 1.32 acres

Access, location and parking: The Pit is 1.5 km east of Maidenhead on the eastern side of the Thames , from the A4(T). The quarry lies within the grounds of Taplow Court . Parking is in Mill Lane . Access is via locked gates, for which permission from owners must be sought.

Site description: Disused quarry, overgrown, but accessible.

Geological interpretation: South Lodge Pit (sometimes known as Taplow Quarry) is the only known British example of Santonian to early Campanian phosphatic chalk. This deposit can be compared to the economic Paris Basin phosphorites. South Lodge displays a high grade phosphatic chalk which can be compared to a similar lithology at Whitecliff on the Isle of Wight . Low grade horizons can also be seen in South erham, Lavant, Boxford, Winterbourne and Downend.

The two levels present at South Lodge contain c. 10% phosphate and appear as brown chalks, although surprisingly the quarry was never used to exploit the phosphate content.

Other features of interest in the quarry are:

·       structural (the dip of the beds is steeper than the regional dip and therefore probably represents a palaeoslope;

·      there are several hardgrounds which represent periods of time when sedimentation ceased or slowed down sufficiently to allow accumulation of fossil material, abundant borings and evidence of cementing activities of organisms on the seafloor and also extra cementation of the horizon itself (the ‘hardground’);

·      fossils are present in several horizons, those of the hardgrounds are most obvious - encrusting annelids, oysters, burrows and foraminifera. Elsewhere other annelids and bivalves are common; also found are echinoids (Micraster and Echinocorys), belemnites, ammonites, crinoids and fish debris, amongst others.

·      layers of tabular and nodular flints.

·      solution pipe (in centre of quarry); this is where water has percolated preferentially through the area of the pipe and dissolved the chalk in this region, infilling the cavity with insoluble debris - in this case phosphatic;

The quarry is therefore of great importance for stratigraphy, geological history of the Late Cretaceous, palaeontology and sedimentology.

Current and potential educational  use (geology, ecology, archaeology, industrial archaeology): No current use is made of the site, as far as is known, as the quarry is fairly overgrown which restricts access to the face. However, there is a good exposure of the chalk within the cliff section visible and this is relatively easily recoverable with site clearance. It is currently unsuitable for group visits. However, the site has great potential as an educational and research resource for all levels of activity and interest. The site also has a wildlife interest in the form of dormice and wildfowl which should be kept in mind during any potential geological plan.

Conservation interest: To maintain the geological integrity of the geological exposure by preventing infill and complete vegetation cover and to clear the obscuring talus. (Vegetation clearance should keep in mind the wildlife interest, particularly the dormice.

Threats to site (present and future): Vegetation - penetration by tree roots disturbs the integrity of the stratigraphy and the smaller sedimentological features, but also prevents access to the site. Infill would be a threat, but the site is under SSSI protective legislation, and there is no immediate threat.

Constraints (basic risk assessment): Rubble and vegetation make the ground difficult and unsafe to traverse. Faces need assessing for stability.

Reference list/bibliography:

Anon. Taplow Quarry ( South Lodge Pit). Contained in the English Nature site files for South Lodge Pit SSSI (unpublished internal report).

Chapman, F. 1892. Microzoa from the Phosphatic Chalk of Taplow. Q. Journal of the Geol. Soc. London. 48, 514-518.

Jukes-Browne, A. J. 1904. The Cretaceous rocks of Britain , III. Memoir of the Geological Society of London , pp. 206-7, 219, 323, 372, 400.

Strachan, A. 1891. Phosphatic Chalk with Belemnitella quadrata, at Taplow. Q. Journal of the Geological Society London . 47, 356-366.

White, H. J. O. 1905. Phosphatic Chalk of Taplow. Q. J. of the Geological Society of London . 61, 461-494.

White, H. J. O. 1910. Geology in the field, p. 224.

Recommendations: Liaise with Natural England with regard to their opinion on whether the site could be made suitable for group visits by clearing, if funds become available.