Churnet Valley: SJ 992479, SJ 992501, SJ 996497, SK 005485, SK 024485, SK 034479
Sandstone outcrops occur along the most elevated parts of the site. Below this the River Churnet has cut through the Upper Carboniferous (Silesian) coal measures exposing both the Crabtree and Two Foot Coal horizons, together with the Froghall Ironstone, all separated by mudstones and siltstones. These exposures have been locally worked within the site, the resulting spoil being generally base-rich even where the surface layers are acidic. The steep valley sides have suffered extensive land slips where flushes and tufa springs are locally frequent. River deposits form the floor of the valley. Coarse-grained gritstones of the Chatsworth Grit type outcrop along the top of Harston Wood. Past land use patterns and the complex geology have resulted in an intricate soil pattern which is reflected in the vegetation.
Source: SSSI citation, English Nature