Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/506

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Mr. Conybeare on the Strata near

cliffs near the town presented very ample and numerous sections of the stratified rock of the country; Mr. Buckland and myself were induced to visit it in the course of an excursion which we made in the west during last summer.

The best access to the town from the Hartland road is by a private carriage way which has been cut through the grounds of Sir James Hamlyn. This not only commands several advantageous views of the lofty and well wooded ravine along the declivity of which it winds, but offers in many places, where the rock has been cut away for the purpose of levelling the road, striking instances of that remarkable configuration of the strata, which is said to be characteristic of the grauwacke formation. To that class all the rocks of this neighbourhood may probably be referred. The principal varieties are those known throughout Devonshire by the appellation of dunstone and shillat; the former answers pretty accurately to the description usually given by mineralogists of that species of grauwacke in which the fragments, supposed to be cemented together by the intervention of a paste resembling the matter of clay slate, are too small to be discerned even by the aid of a considerable magnifier. The latter alternates with the former and is evidently the finer grauwacke slate of the same nomenclature. Of these rocks the coast between Clovelly presents the most magnificent and interesting sections which we met with in the course of our tour. Both varieties sometimes alternating in distinct and well defined strata, sometimes appearing to graduate into each other, and the compact species assuming the external configuration of greenstone or serpentine. The strata inclined in every direction and describing the most capricious and picturesque forms, both curved and angular, open an abundant field of instruction to the geologist, while they present difficulties of which neither the theory