and the other Channel Islands, 21 



The history of this shore is the history of the whole coast as far as 

 Mont Orgueil, where the granitic rock becomes more continuous. 

 The castle itself is situated on a high promontory of it. 



From Mont Orgueil to Rosel harbour, with the exception of a flat 

 shore in St. Catharine's bay, is a continuous cliff, affording no variety 

 of structure, and not intersected by any remarkable veins. 



But at Rosel a very singular rock commences, which appears to 

 occupy the whole of Bouley Bay from Rosel to Belle-Hougue. At 

 a distance it so much resembles the forms of the granites in Corn- 

 wall, that I should have set it down as such had I not examined it 

 at hand. 



It is an argillaceous breccia consisting of large and small scraps of 

 schistus cemented by a basis of the same nature, but having entirely 

 lost its tendency to a schistose fracture. I found some veins of a 

 white hornstone porphyry which run in it. How it is connected 

 with the granitic rock I could not find, but I traced it two miles 

 into the country towards the church of St. Martin. 



The whole remainder of the northern coast consists of rocks of 

 sienite of various elevation, exhibiting generally broad and perpendi- 

 cular faces to the sea. They are every where intersected by per- 

 pendicular veins running N and S, forming many remarkable 

 caverns where they have been exposed to the action of the waves. 



These veins wherever I saw them seemed to consist of granite, of 

 which the felspar was commonly of a brick red colour. The sienite 

 itself is in general white, consisting of variable mixtures of quartz, 

 felspar, and hornblende, and varying therefore in colour. Most 

 commonly the felspar is predominant. 



In the rocks of Mont Mado the felspar is particularly abundant, 

 and is of a flesh colour, constituting a very beautiful variety, which 

 is also susceptible of a fine polish. 



