386 Mr Hill, On, the relative age [May 14, 



further west, N. steep E. : Petit Bot Bay, N.N.W. 60 E.N.E.: 

 Moye Point, N.W. very steep N.E. ; stream half a mile west of 

 Le Gouffre (not distinct) N.N.W. vertical: quarry on cliff at spot 

 marked Prevote Watch House, W.N.W. 60 or 70 S.S.W.: Creux 

 Mahie N.N.W. 60 W.S.W. : Mont Herault, N.W. by N. 60 S.W. 

 by W. From the interior I have only one trustworthy observation. 

 This was made in a quarry south of the brickfield at the head of 

 Les Talbots Road, and showed a strike N. by W. with a dip that 

 .varied in amount from 60° to 80°, but in direction was everywhere 

 towards the west. Turning northwards along the coast of Rocquaine 

 Bay we find well-marked slaty beds at Rocquaine Castle which 

 strike N. and are nearly vertical. On Lihou there are strikes to 

 N.N.E. and N.E. by E. with dips varying from 60 W to vertical. 

 Onwards through Perelle Bay and Vazon Bay there are only 

 imperfect indications, but so far as they go they point to strike 

 N. and dip still vertical. After Vazon Bay the shore is occupied 

 by the Cobo rock and the true gneiss reappears no more. 



Now though the boundary of the gneiss cannot be traced across 

 the interior of the island, yet some idea can be formed of its 

 position. The blue rock of the North is seen in St Peter's itself 

 on the East side of the island, and in some quarries near the 

 Cobo Road on the West, and a sort of scarp runs across the 

 country from near one of these points to near the other. These 

 suggest that this boundary runs on the whole about East and West. 

 This direction cuts right across the troughs and flexures indicated 

 by the above observations of dip and strike. >So far therefore 

 no evidence is yet disclosed in support of the asserted superior 

 position of the gneiss. The more natural conclusion would be 

 that there is either a fault or an unconformity. 



Next let us consider what evidence is afforded by the northern 

 rocks themselves. Under the Esplanade such appearances of 

 dip as can be conjured up are vertical. At Hogue a la Pcrrc 

 some white bands in the rock dip gently S. W. and further N. 

 .a strong joint structure dips gently W. Neither of these indica- 

 tions however are quite satisfactory. The former is neither per- 

 sistent nor continuous : it seems to die out without any obvious 

 reason, and is missing where one would expect to see it again. 

 The latter occurs in a very homogeneous rock, is unaccompanied 

 by any alternation of colours or texture, and seems analogous to 

 cleavage rather than to stratification. Both are gentle, and quite 

 compatible with a different dip within no groat distance. 



. After this for more than three miles along the shore there 

 are few appearances of any bedded structure, and those both 

 unsatisfactory and inconsistent : some are S. and gentle, others N., 

 and many vertical, but there are none in which confidence can 

 be placed. Not till within the last mile of the coast, at Port 



