66 Prof. E. Hull— Submergence of the Isle of Wight . 





valley of denudation that the great synclinal hollow of the North 

 Sea was shaped or cut : a glance at the map will make this quite 

 clear. And this was cut when the connection of England with the 

 Continent was severed, that is, as I have argued in many places, 

 when the Mammoth and its companions were destroyed and the 

 Drift distributed. 



This shows that the bending and moulding of the beds of Chalk 

 in Eastern England into their present contours were comparatively 

 recent events in its geological history, and coincident with the break 

 up and disintegration of the Chalk beds. If this subsidence and 

 bending had been slow and gradual, we should hardly have had the 

 tremendous breakage and ruin of which the evideuce is everywhere 

 most plain. This shows that the breakage was rapid and cata- 

 clysmic, and the result of some great strain suddenly applied — 

 such a strain as occurred frequently enough in the earlier ages of 

 the world, as the interior skeletons of all our mountain ranges show, 

 whenever we examine their crumpled, torn, and dislocated beds, 

 often standing on end. It is strange that the moderate Uniformitarians 

 should allow this in the older times, but be loth to admit it so late 

 as Pleistocene times. 



The conclusions I have here formulated were foreshadowed long 

 ago by at least one writer. The Eev. W. B. Clarke, who wrote 

 so well on Suffolk geology, saj-s in the Geological Transactions for 

 1837 : " While the Crag still lay under the sea, a violent catastrophe 

 broke up many of the Secondary rocks, from the Chalk to the Lias 



inclusive After this period, and probably in prolongation of 



the first great catastrophe, a series of shocks, acting from below, 

 shattered the surface, and gradually elevated the whole district, 

 including the Chalk, till the Crag obtained the height of nearly 

 100 feet above the sea-level ; and by this movement were produced 

 the valleys or lines of fissure through, which the drainage of the 

 country is effected." {Op. cit. second series, v, pp. 367, 368). 



IV. — Post-Pliocene Submergence of the Isle of Wight. 

 By Prof. Edward Huh,, M.A., LL.D., F.R.S., F.G.S. 



TAM tempted to offer a few notes with the conclusions I arrived 

 at during some weeks residence this summer in the Isle of 

 Wight, having been struck with the remarkably definite data which 

 the island affords regarding the maximum depth of the submei'gence 

 (or height of emergence) during the post-Pliocene period. The 

 " plateau-gravels," which are the main factors in the determination 

 of the amount of submergence, have now been mapped by the 

 Geological Survey, 1 together with the other post-Tertiary deposits ; 

 but as regards their mode of formation the Survey (I believe) in its 

 collective capacity refrains from expressing an opinion. 2 I, for my 

 part, have no hesitation in bespeaking for them a marine origin — 

 (1) because of their wide distribution ; (2) because of their elevated 



1 Drift-Maps; Sheets 330, 331, 344, and 34o. 



3 As stated bv Mr. "Whitaker in the discussion on Prof. Preshvich's paper on the 

 " Westleton Beds," QJ.G.S. 1890-91. 



