Geological Survey of the Island of Jersey. 375 



Tourbelaine consists of the same rock as Mount St. Michel : I 

 regret that the state of the tide did not allow me a personal 

 inspection. 



The coast-line to the north of, and in the vicinity of Gran- 

 ville, presents an interesting study of one mode of the natural 

 and gradual conversion of vertical cliff into low and sloping 

 hills. From A to B, the cliffs are generally precipitous enough, 

 partly from having been scarped under the fortification, and 

 partly naturally : at B the sand begins to form, not only an 

 ordinary beach, but also an accumulation, as a glacis, 6, which 

 thus immediately depriving the sea of access to the foot of the 

 cliffs, (from which it not only tears out fragments, but carries 

 them off,) and also forms a hollow, 7, which, sloping north- 

 ward, forms an irregular, but on the whole, connected drain, e, 

 of ponds, which (as in the Jersey Quenvais) entirely prevents 

 encroachments of the same sand, that has already proved an 

 efficient barrier to those of the sea. 



Returning to B, and following the course of the hills, the 

 now undisturbed ecroulements from the top of the cliffs, suc- 

 cessively and gradually present themselves as the ramps 



1' 2' (T 4'l ^ c * unt ^ at a k° ut two miles from Granville the 

 rock entirely disappears, under such a slope as 5 5' 5" covered 

 with grass and a fine soil. 



;.^"K~.-r'-'- 



B, red veins in green. 



