The underlying rock from Bedruthan Steps to Trevose Head is Middle Devonian slates (386–377 Ma) with Staddon Grits to the south towards Trenance Point.
The SSSI is predominantly situated on Devonian sandstones and shales, with the area around St Agnes formed from Grampound grit.
Froggatt Edge is a gritstone escarpment in the Dark Peak area of the Peak District National Park, in Derbyshire, England and situated in close proximity to the villages of Froggatt, Calver, Curbar, Baslow and Grindleford.
Grindleford is popular with walkers and climbers due to its proximity to a variety of landscapes, including open moorland, wooded river valleys (including Padley Gorge), several gritstone escarpments, and the broad Hope Valley.
Laycock grew up in Manchester, England, and was an influential figure in the early development of rock climbing on the gritstone edges of the Peak District of Derbyshire along with his close friends Siegfried Herford, also of Manchester, and Stanley Jeffcoat of Buxton.
The Roaches, a gritstone escarpment in Staffordshire, England
He and John Laycock and Stanley Jeffcoat initiated what is referred to as "gritstone climbing" in England, bouldering on large blocks at the base of the cliffs, and roping up to climb the edges and faces above.
Although focusing on rock climbing in the Peak District, it covers several adjacent cliffs outside this region, and despite its title, referring to the Millstone Grit (or gritstone) geology of many of the cliffs, it includes several cliffs consisting of other rock types, including Mountain Limestone and Red sandstone.