Much of it is chalk grassland which is rich in plants which are rare in Greater London,[1] and it is one of only two sites in London which has the dark green fritillary butterfly.[5] Ten species of orchid and over thirty of butterflies have been recorded.[1] The site also has an area of woodland.
The site was notified to Natural England in 1985, but by 1999 it was in danger of being lost through neglect, and the London Wildlife Trust launched an appeal to save it. The trust aimed to buy the whole site, but only succeeded in purchasing part of it amounting to seventeen acres.[6][7]
There is access from Hanbury Drive and the road Saltbox Hill.