Wasserfledermaus
Within the disused quarries on the western side of the valley, there is a system of caves in which up to 150 bats, of several species, roost in winter. Species which use the site include greater and lesser horseshoe bats, Daubenton's bat, Natterer's bat and Brandt's bat. The quarries have been suggested to be the largest British hibernation roost of the Bechstein's bat, but it remains uncertain whether Bechstein's bats hibernate in caves and mines.