Page:Cornwall; Cambridge county geographies.djvu/40

 24 CORNWALL rising to the surface, a continuation westward of the mass of Dartmoor. It has surged to the surface in four large masses continued westward by the Scilly Isles. These granitic masses have upheaved the superincumbent beds of stratified rocks, partly melting them. These distinct nodes are : the Bodmin moors, the St Austell elevation, the Carn Menelez, and the Land's End district. Smaller The Cheesewring masses of granite occur in the double heights of Godolphin and Tregonning, St Michael's Mount, Carn Brea and Carn Marth, and Castel-an-Dinas. The Elvans are dykes of quartz-porphyry which issue from the granite into the surrounding slates, and are often mistakenly supposed to be a bastard granite. The granite in its upheaval has strangely altered and