ASSOCIATED ROCKS OF THE LIZARD DISTRICT. 891 



intrusive ; but the junction is a remarkably clean one, and the 

 close correspondence in colour adds to the difficulty of seeing 

 it. The serpentine, in places, near the junction exhibits very 

 regular, thin, parallel bands, of a greyish green mineral, and of 

 very lustrous chrysotile, and is in all respects a remarkable variety 

 (no. 6). 



The serpentine is not again seen on the coast till the other side of 

 the bold headland of Pradanack Point, rather more than a mile away 

 in a straight line. The boundary line between it and the hornblende 

 schist, according to the geological map, curves inland, the greatest 

 distance from the sea being a good half mile. I have not traced it, 

 but have examined the serpentine in a small pit, not far from the 

 boundary, on the left bank of the valley mentioned above. Here 

 the rock is rather decomposed and traversed by many joints, coated 

 by a white steatitic film ; in parts it shows some indications of a 

 streaky structure ; the colour is a dull earthy red to brown. The 

 rock is full of minute scales, of a talcose aspect, which gives a 

 glimmering lustre to the broken surfaces. Fracture rather uneven 

 (no. 7). 



The dark crags of hornblende schist which form the northern side 

 of Pradanack headland are singularly grand, as are the cliffs of the 

 next mass of serpentine. The junction here is difficult, to examine. 

 A small gully seaming the face of the cliff marks it, as is often the 

 case ; but though we spent some time in careful search over the 

 accessible parts, we could find no actual contact, though we traced 

 the two up to within a yard of each other. This mass of serpentine 

 is also dark ; a specimen obtained a few yards from the gully is of a 

 dull olive, approaching black (streaky structure clearly indicated by 

 paler lines), rather unequal fracture, and lustreless surface ; joints 

 coated with paler greenish films. The hornblende schist is much 

 broken and disturbed near the junction, and looks as if in the vicinity 

 of an intrusive rock. The dip, in a glen a little south of the above 

 spot, was 55° E.N.E. 



The celebrated Mullion Cove is the end of a valley which very 

 nearly defines the northern limit of this mass of serpentine ; it is, 

 however, cut everywhere through the hornblende schist. The actual 

 junction is masked by debris ; so this also is inconclusive. 



The serpentine at the northern end varies : most of it is dark dull 

 green to black ; but in one place it assumes a redder tint. A common 

 variety has a dark, almost black, matrix, full of small scales of glit- 

 tering mineral, similar to, but darker than, those at Pradanack (no. 8). 

 A fine sea-cave here well repays a visit. 



A very short distance beyond the cove is another mass of serpen- 

 tine, not marked in the map, dull in colour, streaky in structure, 

 resembling that in the southern part of that which has just been 

 mentioned. There is sometimes a little difficulty in tracing the exact 

 junction of this and the hornblende schist ; but there can be no doubt 

 that the serpentine is intrusive ; on the northern side, against the 

 cliff, is an included fragment of the schist. Again, the headland to 

 the west of the above is serpentine, with two included fragments of 



