SUPERFICIAL DEPOSITS. 217 



of the accuracy of this estimate, and at my request Colonel 

 Dove, R.E., was kind enough to make a fresh measurement. 

 He found that the lowest part is 125 feet above mean tide 

 level, or about 105 feet above spring tide high water mark. 

 The top of the depression is some ten or twelve feet higher. 



There is a very interesting raised beach shown on the sides 

 of the main road near St. Clement's Church. It is about 600 

 yards distant from the nearest part of the coast, and its average 

 height is probably some 50 or 60 feet above high water mark. 

 The pebbles are smoothly rounded pieces of diorite and fine 

 red granite, and they lie on decomposing diorite, which slopes, 

 first abruptly, and then gently beneath them. Over this 

 beach is a bed of yellow clay or brick earth,. rising with the 

 slope of the ground through which the road is cut, from two 

 or three to about fifteen feet in thickness. 



Passing through the middle of this clay there is a straight 

 sloping line of angular fragments of fine red granite, amongst 

 which, the other day, I found a round pebble of the same 

 rock. These fragments are mostly from one to six or eight 

 inches in their greatest length. Near the lower or western 

 end of the section, however, there is a block whose projecting 

 sides measure 1ft. 4in., 1ft. 2in. and 2ft. 7in. respectively. It 

 may be mentioned that the nearest outcrop of granite is 

 440 feet distant from the block, to the east of the upper end 

 of the section, and some thirty feet above its level. 



There are some high level beaches on the north coast of 

 the island, to which my attention has been directed by Mr. Gr. 

 A. Piquet, but unfortunately I have never found time to visit 

 them. I have seen excellent photographs taken by Mr. 

 Piquet of one attached to the roof of a cave, and one in the 

 upper part of a cave or fissure. They are 35 or 40 feet above 

 the beach which forms the floor, but I am not sure of their 

 height above spring tide high water mark. 



In Guernsey the highest beaches do not seem to be 

 covered by clay or head ; but in Jersey, with the exception of 

 those just mentioned on the north coast, and perhaps one on 

 the east coast, all the high level beaches are covered by or 

 embedded in the clay. In one beach, where the pebbles are 

 included in the clay, the stones form a layer a foot or two 

 above the basement rock ; in two other instances there is a 

 great depth of clay beneath the deposit, the exact depth 

 in both not being ascertainable on account of the nature 

 of the section. In one of these there is at least ten feet of 

 clay between the layer of pebbles and the bottom of the section, 

 which is formed by a road, and it probably extends to a 



