Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/1023

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ASSOCIATED ROCKS OF THE LIZARD DISTRICT.
893

and mineral character of the rock are perfectly distinct. Other smaller masses, included in the serpentine, will be noticed on the shore, in some cases indicating by their peculiar jointing that they

Fig. 1.—Irregular Strip of Hornblende Schist caught up by Serpentine.

A. Hornblende schist. (The parts shaded by fine lines are serpentine.)

have been subjected to heat. Clambering on at the base of the serpentine crags, we enter a small bay with a narrow shore, almost divided into two by a slight projection. Soon after entering the nearer of these we pass, at the base of the cliff, two small intrusive gabbro veins, the nearer at most about two feet thick and branching, the other about half as much. The rock is dark in colour, partly owing to staining from the serpentine, and rather coarse. This bay also exhibits well the relations of the schist and serpentine. The luxuriant herbage generally masks actual junctions, except in one place near the base of the cliff, where the serpentine may be seen gradually passing across the broken ends of the beds in the schist; but without this evidence the relations of the schist and serpentine in the cliff cannot be wholly explained by faults.

Fig. 2.—Foliated Gabbro Vein in Hornblende Schist at the Balk.
A gabbro vein in the hornblende schist should be noticed; it is about half a yard thick, and in form a rude rhomboid (fig. 2). It exhibits a