I. Introduction. On mapping the country to the north of Bodmin Moor for the Geological Survey, it was found that the slate-rocks, as noted by Mr. John Parkinson, are separable into several well-marked lithological types. These types are of widespread occurrence, and strike across the country in parallel zones in a general west-north-westerly and east-south-easterly direction with a constant dip to the north-north-east. But, although this stratigraphical succession occurs over so wide an area, it apparently broke down in the Tintagel district, where a repetition of the strata was found near the coast. Subsequent investigation, however, proved the repetition to be due to overthrusts from the west-north-west. With the district affected by overthrusts I propose to deal in the present paper. Several observers have written about the geology of Tintagel, but as none of them interpreted the structure, it, is only ,ecessary to give references to their papers in the following list :— II. Description of the Area covered by the Map (Pl. XIII). The area represented on the map covers about 5 square miles, with about 4 miles of coast-line. The district forms a plateau ending off in cliffs which are between 300 and 400 feet high. A portion of a still higher plateau rising to 600 feet occurs in the south-eastern corner of the map. Two small streams dissect the lower plateau, the one on the north forming the Rocky Valley ; and the other, on the west, the Trevena Valley. The whole area forms a land-mass which
Read full abstract