The Onny Trail, near Craven Arms, follows river and old railway exposures through an important Ordovician succession. Brachiopods, trilobites and other marine fossils accompany two very different geological contacts: Silurian strata above Ordovician rocks and, farther along the route, Ordovician grit above ancient Longmyndian basement. The historic five-area walk requires current access and safety checks. Silurian, Ordovician, Cuttings, Stream, and Disused Quarry, Rating: ♦♦♦