ASSOCIATED ROCKS OF THE LIZARD DISTRICT. 889 



tine. Finally, a granite vein has cut irregularly through all these 

 rocks. 



The rock (4) is not easy to determine ; its texture is coarser on 

 the face of the crag than it is along the outcrop a few feet back ; I 

 have had slides prepared from each part. The finer variety consists 

 of an interwoven mass of rather acicular crystals of hornblende 

 (actinolite), in a clear base, which, with crossed prisms, either remains 

 dark or exhibits an obscure microcrystalline structure. This in parts 

 seems to resemble steatite ; in others it is more like one of the 

 pseudomorphic products after felspar, which will be noticed below. 

 Granules of magnetite* are scattered about ; and there are some very 

 irregular grains or plates of a brown hornblende, full in many parts 

 of a black dust. This mineral appears, from its cleavage, to have a 

 platy structure. In the coarser specimen there appears still more acti- 

 nolite, and the brown hornblende grains are much larger ; they appear 

 in some cases to have been broken or partly destroyed after they 

 had been formed. The mineral to the eye has a clove-brown colour ; 

 it much resembles anthophyllite, but is certainly not an ortho- 

 rhombic mineral ; probably it is the variety of hornblende noticed 

 by Rosenbusch (Mikr. Phys. p. 264). I believe that this rock was 

 originally a hornblende schist, that its entanglement with the in- 

 trusive rock affected it to some extent, and that since then it has 

 undergone further changes, chiefly by the action of water. 



Nearly above this place, at the top of the cliff (the Rill), is a land- 

 slip, or a deserted quarry, of considerable size. Here are two granite 

 veins in the serpentine — one about 4 feet wide, forming a curved dyke 

 running up the face of the higher cliff, the other showing in it a short 

 distance towards the south. Both are much decomposed and of a red 

 colour ; they crack the serpentine in contact considerably ; and in 

 places it is so much altered that for a few inches it might be taken 

 for a talcose schist. We have thus an irregular line of veins and 

 small bosses of granite extending pretty continuously over more than 

 half a mile. The serpentine forming the cliff just mentioned is 

 compact in texture, of a dull purplish colour ; the bronzite crystals 

 are few and small (no. 4). When examined carefully the rock 

 shows a sort of parallel streaky structure, indicated by darker lines ; 

 the faces of the joints are coated by films of green or whitish steatite ; 

 and old surfaces weather dark rusty brown. The parallel structure 

 becomes much developed by the weathering, and might easily induce 

 the supposition that the rock was really stratified. It is par- 

 ticularly well exhibited along the down to the north of Kynance 

 Cove, though it may also be observed to the south of it, as in other 

 places. In the coarser varieties the structure appears to be formed 

 by bronzite crystals, which have resisted weathering better than the 

 matrix in which they are imbedded. 



* To save time, I shall use this term for the opaque mineral, obviously an 

 oxide of iron, common in many of the rocks described below. As, however, it 

 generally occurs in small rounded grains, I cannot be sure that it is always mag- 

 netite, since it may be ilmenite. Chromic iron has been found in serpentine 

 near Cadgwith (Trans. R. Gr. S. Corn. ix. 99). 



