Geological Survey of the Island of Jersey. 363 



14. Felspar, Quartz, and Green Mica (Felspar, red). 

 50, 51, 53. Felspar, Quartz, and Common Mica, ditto. 



Felspar alone. 

 1. This rock forms the sharp, prominent, and weather-worn 

 columnar peaks along the coast from Tremont to the point p 

 in Boluey bay, where it comes in contact with the breccia : in 

 the same manner it runs from r to s, until it is overlaid by the 

 sienite at Mont Orgueil. It seems to pass into two rocks ; at 

 t (in the Trinity valley) it forms peaks to 36 ; and all round 

 the coast, as above pointed out, it invariably indicates 2, 3, and 

 10 below. Where exposed to the weather, its external surface, 

 for about an inch in depth, sometimes breaks and cracks into 

 facets, but without becoming soft. 



LJ 



26, 27, 28. I can only find these in the immediate neigh- 

 bourhood of the argillaceous schist, as at Gallows Hill, round 

 St. Saviour's, and at Gouray, accompanying the large bed*. 

 It is the only one of the felspar rocks that in anywise inter- 

 mixes with this last, which in this case assumes the form of a 

 very compact writing slate, as a matrix containing dispersed 

 but fairly mixed portions of the green specular porphyry. Its 

 relative position, with respect to the argillaceous schist, as 

 distinct from it, on the whole is shewn very decidedly at /, 

 near the Town Mills. 



Arg. Schist 



Porph. 



It is a very imperfectly stratified rock, not homogeneous in 



* Also in a vein of argillaceous schist near Noir Mont. 

 oct.— dec 1829. 2 B 



