52 W. Whitaher — Geology of Coasts of England and Wales. 



from Roman times onward. This gained land, however, does not 

 aid in protecting the open coast ; it is merely the infilling of a great 

 hollow, and this infilling can never be carried beyond the coast- 

 line, even if it ever reaches up to that. It is certainly valuable land, 

 more so than much of that which is lost along the coast. 



Another variety of accretion of land is where the sea piles up a mass 

 of shingle, well above high water mark. This may form a strip along 

 the coast (as in ordinary beaches) ; or may extend as a long slip 

 between a river and the sea (as near Aldeburgh) ; or may form 

 a broader tract, brought about by successive piling up of fulls or bars 

 of beach to a considerable extent, so that the sea gradually forces 

 itself outward from the land (as at Dungeness). [There is yet 

 another rare mode of occurrence, where a beach (as the Chesil Beach) 

 joins what would otherwise be an island to the mainland.] 



Such tracts of shingle are, of course, of no value as ordinary land, 

 but they have a great influence on the coast. 



Ckustal Movements that may be going on oe which have 



OCCUllRED IN LATE GeOLOGIC TiME. 



I can only say on this question that I know of no good evidence of 

 movements now going on. But there is clear evidence of such movemeiits 

 having taken place in late geologic times. Thus the common occurrence 

 of what have been called submerged forests shows that the land, at 

 a very late geologic period, must have been a little higher than now. 

 I object to the name given to these occurrences, as it seems to me 

 misleading; there are no large forests, but only the occasional 

 roots of trees and other remains of wood (see post). These, 

 moreover, do not occur continuously along a great line of coast ; so far 

 as I know, they occur only in the neighbourhood of river-mouths. 

 They are, in fact, nothing but a part of the alluvial flats of river- 

 valleys, valleys that have been cut back by the advance of the sea, so 

 that their latest deposits are shown at low water, where the valleys 

 now end, that is, at the coast. These peaty beds really have no 

 connection with the coast ; they occur up the valleys also, and we 

 have a notable instance of this in the Valley of the Thames, from 

 London downward, where these beds have been laid open in the large 

 excavations for docks and basins which have been carried to some 

 depth below sea-level, or in the long trenches that have been dug for 

 main drainage. 



One of the most marked occurrences of such beds along a fair extent 

 of coast is in the peninsula of Wirral, between the estuaries of the 

 Dee and of the Mersey and on the other side of the latter, where the 

 peat, crowded with roots of trees in the position of growth, can be 

 well seen. The trees in these beds are of the same kind as those now 

 growing in the country, and it is clear that they could not have grown 

 in their present position, some feet below high-water mark : they 

 must have lived when the land was at a slightly higher level than 

 now. It is important to remember that they have nothing to do with 

 the coast, but only with the river-valleys and their former extension. 

 They occur in the case of small streams as well as in that of large 



