John Kidd

“ David's slate quarry, by a low and narrow ridge of rocks projecting into the sea; and is terminated at its southern extremity by high cliffs. Towards the land it is bounded principally by heaps of sand; interspersed with low rocky cliffs, which rise higher and higher in advancing to the southern extremity; at which point the rocks are particularly interesting from their variety; passing, sometimes abruptly, from the coarsest grained conglomerate, as from its appearance it might be called, to the finest schist. ”

“ The hornblende of the summit of this hill is indistinctly crystallized, and of a dark and dull olive green colour; generally very uniform in its character; and so closely compacted with the felspar that the fracture passes indiscriminately through both. The rock itself is remarkably hard, and has that degree of toughness which is characteristic of the class of rocks called by Wallerius Saxa Cornea, and Corneus Trapezius; which rocks, as may be collected from the volcanic dissertations of Dolomieu and Ferrara, contain hornblende as a principally constituent part. ”

“ The general character of the rocks in the neighbourhood of Treginnys is of that equivocal nature alluded to in the beginning of these notes: here and there they assume the appearance of a compact earthy felspar of an olive-green colour, and then probably often contain epidote, compact veins and crystals of which I saw in more than one instance. In one place this compact green rock occurs in angular columns horizontally aggregated, and forming a part of the cliffs on the north side of the harbour. ”

“ From the summit of Carnllidy the ground gradually slopes towards the west for a few hundred yards, and then, again rising, forms the promontory called St. David's Head.
The ascent to the two hills above mentioned, both on the north and on the south side, is formed by highly inclined strata of a slaty rock which would be commonly called grau-wacke, a term in the present instance used only for the purpose of general description; and the nearly precipitous cliffs, by which the greater part of the adjoining coast is bounded for some miles, appear to consist principally of the same kind of rock. ”

“ The rocks which constitute these hills bear no marks of regular stratification; rarely support even a slight degree of vegetation; and when compared with the surrounding surface, appear as so many nuclei, about which is arranged a very curiously diversified series of highly inclined strata of a kind of slate. The constituent parts of these insulated rocks are felspar and hornblende; and the general character of them is crystalline: but the felspar rarely if ever occurs in distinct crystals ”

“ Again, though the mass often appears upon the whole to have been of chemical origin, yet at the same time it is, partially, of a structure to the eye decidedly mechanical; and in some instances the character is so extremely equivocal as to leave the judgment in a very difficult state of suspense. ”

“ The predominating colour of these crystalline rocks is a brownish green.
The two highest of these hills, called Carnllidy and Penberry, are situated to the north of St. David's: they rise less abruptly from the plain than the similar hills of the neighbourhood; and are in a manner connected with each other, and with a third summit not far distant from the last mentioned, by a slightly elevated ridge which passes in a south-westerly direction from one hill to the other ”