Notices from the Minute Books of the Geological Society. 567 



tentin, to the north ; the existence of a series of faults in Dorset ranging in a linear 

 direction with the elevated beds of the Cotentin, as well as another transverse se- 

 ries on the coasts of England and France, are conditions which appear to agree so 

 accurately under all their bearings, as to induce, the author says, the supposition, 

 that the tract now occupied by the English Channel between Cape La Hogue and 

 Portland owes its existence to a denudation of deposits intermediate between the 

 slate and the oolites, in the direction of the similar but minor valleys in La Manche • 

 and that the appearances of elevation so extensively developed on both sides of the 

 Channel owe their origin to one common, deep-seated cause, evidence of which is 

 afforded in the traps and granites of La Manche, Brittany, Devonshire, Cornwall, 

 and the Channel Islands. Lastly, with reference to the belief which had been en- 

 tertained by a previous observer, that the western coast of the Cotentin may have 

 originated in a fracture, Mr. Clarke observes, that there is reason to infer that the 

 coast-lines, not only of the Cotentin, but of the Channel Islands, Purbeck and the 

 Isle of Wight, will be found to have been produced by a series of contemporaneous 

 or successive upheavings of the strata in the same linear direction, at an epoch 

 posterior to the formation of the tertiary deposits. 



2. Extract from a Letter dated Marciana, Elba, Sept. 1, 1837, addressed to the Rev. 

 William Buckland, D.D., V.P.G.S. By Walter Calverly Trevelyan, Esq., 

 F.G.S. (Read Nov. 15, 1837.) 



" On the shore near the point where the road descends towards the rock or islet 

 of Lihou, on the east of Guernsey, may be seen a section, in which, above the 

 present high-water mark, the granite rock bears evident signs of having been worn 

 by the action of the waves, previously to the deposition on it of a bed of gravel, 

 which now covers the granite and fills up the inequalities of its surface. The gravel, 

 which is firmly bound together by a ferruginous sand, consists of pebbles of the 

 neighbouring rocks, also of chalk flints, some not much rounded ; and it extends to 

 about eight feet above the present high-water mark, ranging also apparently a little 

 inland. On the gravel is a bed, about three feet thick, of disintegrated granite, 

 mixed with angular fragments of that rock and covered by the surface soil." 



On the north-west side of the island, near Fort Doyle, a similar gravel occurs, 

 about eight feet above high-water mark, resting principally on the surface of the 

 syenite rocks of a low cliff, but occupying also fissures, which Mr. Trevelyan is of 

 opinion, were formed during a slight elevatory movement, and into which he be- 



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