Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/308

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of granite, and the rocks which rise above the surface, about a quarter of a mile to the south, are of the same nature. On the eastern side, the greenstone I have described, § 17, forms the prevailing rock. I found in this place, another compound of hornblende and felspar, which has perhaps more distinctly the appearance of a greenstone than the other. The constituent parts are larger grained, and the felspar is white : magnetic pyrites are disseminated through the mass.

§ 28. About the middle of the hill on this side, I found a rock of a brownish olive colour, of a close texture, with an uneven fracture, and, as far as the fineness of the grain enables me to determine, composed of hornblende and felspar, but chiefly the former; there are also some detached portions of calcareous spar imbedded in it. It is attracted by the magnet. When broken, it appears full of angular fragments; and I in consequence considered it of secondary formation, but when the fracture is made across the fragments, they are found to be composed of the same materials as the base in which they appear imbedded, nor can they be distinguished from it; I am therefore of opinion, that the fragmented appearance arises from a disposition in the rock to split into small irregular pieces with decomposed surfaces, a peculiarity I have already noticed as being common to most of the unstratified rocks of the Malvern hills.

§29. In a lower part of the hill, and close by the high road, there is a very loosely aggregated red and white quartzose sandstone, accompanied with patches of reddish-brown clay, containing fragments of a granitic rock, and of the sandstone itself. The situation of this sandstone is remarkable; it occurs at a considerable height above the plain, it offers no signs of stratification, and is of very small extent, lying as it were in a hollow of the other rocks. It is very similar to what is found in the plain below, except that the latter contains some