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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 22, 



3. On the Superficial Accumulations of the Coasts of the En- 

 glish Channel, and the changes they indicate. By R. A. C. 

 Austen, Esq., F.R.S., G.S. &c. 



The geological phenomena which form the subject of the present 

 communication have hitherto been included under notices of " Raised 

 Beaches," or of " Recent Changes of Level ; " they have invariably 

 been considered as illustrations of the latest vertical movements of 

 the earth's crust, as referable to one single period of time, and as 

 mostly of small amount. My object will be to show that the phseno- 

 mena in question are much more complicated, that they imply a vast 

 period of time, that one most important character has been entirely 

 overlooked, and that taken together they help to explain the history 

 of what is perhaps the most striking of the changes in its physical 

 conditions which the Northern hemisphere has experienced — namely 

 those which occurred during the Pleistocene period. 



The consideration of the evidence which any one of these masses, 

 known as raised beaches, presents, will be the best introduction to 

 the notices which follow. It must be borne in mind that no traces 

 of such accumulations, sufficiently clear for our purpose, will be found 

 along those parts of the coast-line of the English Channel which con- 

 sist of yielding strata ; from which we may infer that the period 

 of the present sea-level has been of sufficient continuance to allow of 

 the cutting bach of such coast-line to points beyond the original ex- 

 tension inland of such accumulations. 



The phsenomena to be described are to be first observed on the 

 coast of Devon, at the point where the older slates and limestones 



Fig. 1 . — Section West of the Entrance into Dartmouth Harbour. 



e 



a. Level of Fucus vesiculosus. 



b. Zone without marine vegetation. 



c. Upper tidal zone of a former level. 



c'. Upper level of old marine beds, in former 



e. Ancient sea-cliff. 



/. Subaerial beds. Thick accumulations of 



earthy materials, with angular fragments 



sea-cliff. 



d. Surface bed of vegetable mould, formed out 



and blocks of slate. 

 g. Slate-rock. 



of a bed of marine sand and shingle. 



emerge from beneath the new red sandstone, and they are thence 

 continued on interruptedly ; the completeness with which they are 

 presented depends much, even there, on the manner in which the 



