6 PROF. T. G. BONNET ON THE HORNBLENDIC AND OTHER 



little prominence occupied by a boat-house, has a remarkable grit- 

 like aspect (see microscopic description, p. 18). There is much local 

 disturbance, but the general dip is about 25° N.E. On the north 

 side of the cove serpentine with intrusive gabbro rises to the top of 

 the cliff; these continue for a short distance till a second small cove 

 is reached, bounded on the south by dark serpentine * and intrusive 

 gabbro, both of which break through the granulitic group, and on 

 the north by the normal dark hornblende schist. The cove itself 

 follows the line of faulting, by which the rock for a short distance 

 seems completely ' smashed.' 



The latter group was examined from above down to the sea at 

 Carnbarrow. It is the normal dark hornblende schist, with the usual 

 specks and imperfect bands of white felspar, which in one place shows 

 remarkable indications of current-bedding. The beds dip to N.E. or 

 a little N. of this at about 20° to 30°. In the small quarry above 

 Dolor Hugo, where the general dip is about N.E., the highest rock 

 begins to bear some resemblance to the granulitic group. The sedi- 

 mentary beds on either side of the " Prying Pan" belong to the 

 granulitic group, and though locally much disturbed by intrusions of 

 serpentine, appear to have a general dip to the N.N.E. at about 20°. 



A great fault passes down Cadgwith Cove and brings in again the 

 dark hornblende schist with epidotic bands and indications of current- 

 bedding (p. 16), similar to what we find above the middle part of 

 this group. The general dip is between N.N.W. and N.W., and 

 about 35°. 



These dark hornblendic rocks continue with a fairly steady dip 

 until, after passing another small cove, we come to the (red) serpen- 

 tine quarry on Tnys Head, where that rock is intrusive in a mass of 

 the granulitic group, which also crops out among the serpentine in 

 the headland immediately to the north. The general dip of the 

 stratified series is north-westerly, and at about 30°. A little beyond 

 is a bowl-like corrie with indications of a landslip, which leads us 

 down to the sea. Here we have the black serpentine breaking through 

 and overlying the granulitic group, which is exposed in at least three 

 places, the largest mass, on the southern side of the recess, dipping 

 roughly W.N.W. A thick dyke of coarse gabbro, conspicuously 

 foliated towards the exterior, runs obliquely up the cliff. Some of the 

 diallage crystals are of great size ; one, which appeared fairly unin- 

 terrupted, was more than four inches across. 



The sedimentary rocks seen on each side of Caerleon Covef, de- 

 scribed in my last paper, belong to the granulitic group with pseudo- 

 granitic bands as at the Balk. In some cases the layers of granitoid 

 and of dark hornblendic or micaceous rock alternate rapidly, the 

 thickness being from 3" downwards. 



The details of the coast rock of Caerleon are given in my former 

 paper, as well as those in Kennack, so that it will suffice to say that 

 the sedimentary rocks belong to the granulitic group, and in the 



* The variety found abundantly north of Cadgwith. 



t I again examined the dioritedyke (described p. 900). I am now quite sure 

 that there is no hornblende schist entangled in it. 



