The calcareous soils have developed on Lower Lias clays, fuller's earth and oolitic limestone strata of Jurassic age.

Pockets of ancient woodland on the lower slopes are home to woodpeckers, and unusual plants such as Bath asparagus.

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).

Boris, the oldest Greater Horseshoe Bat ever recorded in Britain, was discovered at Browne's Folly in January 2000.

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.