THE 



GEOLOGICAL MAGAZINE. 



No. LXIV.— OCTOBER, 1869. 



(D:Eix<3rXisrj^Xj ^^s-tiolibs. 



I. — On the Formation of the Chesil Bank, Dorset. 



By Henry William Bristow, F.R.S., P.G.S., and William Whitaker, B.A. 

 (Lond.), F.G.S., both of the Geological Survey of England. 



[PLATES XIV. & XV.] 



[A Paper read before the Geological Society of London, May 26, 1869.] 



* * * * " Aloft where Chesill, lifts 



Her ridged snake-like sands, in wrecks and smouldring drifts, 



Which, by the South-wind raysd, are heav'd on little hills : 



Whose valleys with his flowes when foming Neptune fills, 



Vpon a thousand swaunes the naked Sea-Nymphes ride 



Within the ouzie Pooles, replenisht euery Tide : 



Which running on, the Isle of Portland pointeth out." 



Poly-olbion, by Michael Drayton, Esq., Fol., Lond., 1613, p. 24.' 



WE do not propose to enter into the questions of the source whence 

 the pebbles of the Chesil Beach are derived, nor of the way in 

 which they are heaped up ; these and other like matters having been 

 almost exhaustively treated by Mr. J. Coode,^ to whose paper we 

 refer the reader for a detailed account of the bank. The subject 

 with which we propose to deal is simply the cause of the formation of 

 a long shingle-bank, separated from the mainland by a strip of 

 water. This has not been noticed at length by any writer, as far as 

 we know, though three theories of the origin of the bank have been 

 brought forward. 



Sir Henry De la Beche is the author of one of these. He says : " It 

 (the Chesil bank) protects land which has evidently never been ex- 

 posed to the destructive fury of the Atlantic swell and seas, which 

 break with fury against the bank ; for the land behind is composed 

 of soft and easily disintegrated strata, which Avould speedily give 

 way before such a power. Perhaps a gradual sinking of the land 



1 Judging from the quaint map that accompanies this description, tbe Chesil 

 bank must have been much the same in Drayton's time as now. However, all the 

 nymphs that wo saw were more or less clothed. The general appearance of the coast 

 in question is shown in Plate XV., which is from a sketch made by Mr. Bristow 

 twenty years ago ; being a vieiu of the Chesil Bank and the " Fleet " or '* Backwater," 

 looking westivard from near Fleet House. 



2 Proc. Inst. Civ. Eng., vol. xii., p. 520 (1853). 



VOL. VI, — NO. LXIV. 28 



