A HISTORY OF CORNWALL northern end of Constantine Bay is a new species of Conularla. It occurs on the surfaces of the shales as nearly black flattened fragments, which often retain the surface markings. In these surface markings this form, according to Dr. Hinde, differs from all the other examples of Conularia known from the Devonian rocks of America and Germany, principally in the marked fineness of the transverse lines, and it probably belongs to a new species. There was not a single example of this genus from the Devonian rocks of this country either in the British Natural History Museum or in the Museum in Jermyn Street in 1894, when some speci- mens were given to them by Dr. Hinde. Two large pyritized forms resembling Crustacea 15 to 18 inches long, were found here, one of which is deposited in the Penzance Museum. The slates on the isthmus of Dinas Head show some organisms, but the chief interest of this projection from Trevose Head is the ex- posure of nearly an acre of a soda-felspar rock, weathering white, with a chert-like appearance and fracture, and supposed to be a sedimentary rock altered by contact with the igneous rock of which the peninsula is composed. This rock contains about 10 per cent of soda. 1 Similar porcellanized slates are seen in many of the greenstone promontories north of this and at Lundy Beach near Port Quin, north of the Camel, where the rock contains 9*35 per cent of soda and '39 per cent of potash. East of Trevose Head lies Mother Ivey's Bay, where at the east end of the beach a shelf of blue slate near high water mark has yielded Tenta- cu/ites, small brachiopods, Centronella, a form allied to Retzia longirostris y Orthoceras, and a specimen of Hyolitbes, all pyritized. This locality has become famous recently by the discovery of a fragment of a large new trilobite, Homalonotus Barratti, so named by Dr. H. Woodward, F.R.S., in honour of the discoverer. 2 We next reach Cataclews Point, famous for its variety of igneous rocks. It gives its name to a stone that has been quarried for centuries for archi- tectural purposes. The tomb of Prior Vivian in Bodmin church is an example of its durability and value. It is a fine grained greenstone, for the most part an altered picrite. Harlyn Bay is more famous for its pre- historic cemetery than for older remains, and New Train Bay introduces us to Trevone, which has proved a storehouse of interest. The fossils are mostly pyritized, and unfortunately the scour of the sand is not sufficiently severe to weather fresh fossils rapidly. Trevone cliffs and foreshore have yielded Orthoceras^ Bactrites, Goniatites, Euompbalus, Tentaculites, trilobites, corals, brachiopods, Styliola, and two fossils characteristic of Upper Devonian rocks, viz. Bactrites budesheimensis, F. Roemer, and Cardiola retrostriata, Von Buch. 3 Trevone Bay is bounded on the north by Roundhole Point, and the northern side of this promontory is composed of the noted ' Marble Cliffs, 1 Described Geol. Mag, decade iv. vol. ii. No. 367, 1895. Vide Geol. Mag. No. 463, January, 1903, pp. z8~3i. 3 Vide Trans. R. Geol. Sac. Corn. xii. 535-45. 40
