The quarry workings provided stone for the façade of Buckingham Palace. The underground workings are of great speleological and historical interest; they are well decorated and contain many delicate stalactites and examples of gull formation (caves features formed by land slippage).
The disused underground quarries are used for roosting by the Greater Horseshoe Bat,[4] and five other bat species are present at the site.[2] The main bat roost area is clearly marked on the survey created by the SMCC, and everyone is asked to avoid the area. Boris, the oldest Greater Horseshoe Bat ever recorded in Britain, was discovered at Browne's Folly in January 2000.[5] The SSSI forms part of the Bath and Bradford-on-Avon Bats Special Area of Conservation.[6]
Access
In 2000, access was unilaterally withdrawn by the Avon Wildlife Trust pending the results of a mine inspector's report on the safety of the mines. This report was required because of the Health and Safety at Work Act which affects employees and volunteers of Avon Wildlife Trust who might have to enter the mine to count the bats. These legal requirements do not affect leisure access by cavers. Prior to 2000, access to the mine was controlled by the Council of Southern Caving Clubs and cavers coexisted with a thriving bat population with voluntary restrictions on access during the bat roosting season.
^ abc"Brown's Folly"(PDF). Site of Special Scientific Interest (SSSI). English Nature. Archived from the original(PDF) on 3 March 2016. Retrieved 2 June 2008.
^ abGreen, Ian (2000). Myles, Sarah (ed.). The Flora of the Bristol Region. Wildlife of the Bristol Region. Pisces Publications. ISBN978-1-874357-18-6.
^"Brown's Folly". Reserves. Avon Wildlife Trust. Archived from the original on 26 September 2011. Retrieved 2 June 2008.
^"Browns Folly". Avon Wildlife Trust. Archived from the original on 26 September 2011. Retrieved 11 November 2011.