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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 22, 



The accumulations here described are exceedingly well exhibited in 

 the Channel Islands, and will he there seen in many coast sections to 

 attain a vast thickness ; in such cases there is always high ground 

 above from which the materials have been derived. Some geologists 

 might, I imagine, at first sight be inclined to consider these masses 

 to be simply the result of the surface decomposition of the granite. 

 In these islands, however, there are numerous opportunities of ob- 

 serving the beds of decomposed, but undisturbed granite, for the pro- 

 cess has in places extended to a great depth ; these beds throughout 

 their thickness, whatever it may be, show the veins and harder 

 nodules occupying their natural places in the mass, and such nodules, 

 if detached, are globular and never angular, as are the fragments in- 

 cluded in the detritus beds with which we are now concerned : be- 

 sides this, the blocks when derived from crystalline rocks have the 

 precise angular forms into which such masses are naturally jointed ; 

 and with respect to the slates, the fragments have evidently resulted 

 from a forcible splitting up of their planes of cleavage. 



On such considerations as the foregoing, and also from the ter- 

 restrial conditions with which these accumulations are connected, I 

 have proposed to consider this portion of the series of superficial beds 

 as of sub-aerial origin (Report of Geol. Sect. British Assoc. 1849 ; 

 Quart. Journ. Geol. Soc. vol. vi. p. 94). It only remains for me to 

 add, that the thickness and positions of these beds are well repre- 

 sented in Sir Henry De la Beche's Sectional Views of the coast at 

 Fistral Bay, New Quay, Braunton Barrows, Nelly's Cove, and between 

 Rose-mulleon and Main-port ; Report on Devon and Cornwall, by 

 myself, in Trans. Geol. Soc. vol. vi. p. 441. They have been noticed 

 by Prof. Sedgwick and Sir R. Murchison, in a paper " On the raised 

 marine beds of Boggy Point" (Trans. G. S. vol. v.) : "We there 

 found," they observe, "that the top of this under-clifT was occupied 

 to a depth of 8 or 10 feet, by a mixed detritus of angular fragments 

 of the adjacent rocks, contained in a matrix of sandy loam." 



The portion of the superficial accumulation of the Sussex coast 

 which Dr. Mantell has designated as the "Elephant bed" is of the 

 same age and has originated under like sub-aerial conditions with 

 those here described. It presents like characters of successive increase, 

 and is composed of materials, such as the chalk-flints in particular, 

 which, as observed by Dr. Mantell, have every appearance of having 

 been exposed to the action of the atmosphere for a considerable 

 time. 



§ 4. In the section No. 4. PI. VI., and in fig. 1, the beds which form 

 the base of the vertical cliff (e) and underlie the accumulations last 

 described, consist of coarse marine gravels, shingle, and sands, resting 

 on an uneven surface of slate-rock, of which they fill up all the in- 

 equalities : they correspond at some places with the materials of the 

 sea-bed of slight depths, and from this condition they are to be found 

 of every intermediate stage, up to that of loose sand of high-water 

 range. The sea-beds may in most cases be followed to some short 

 distance, with a gradual rise, until they meet the base of a line of steep 

 slope or cliff — the former coast-line of this period of level ; this fea- 



