﻿286 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 25, 



These gravel-beds are continued from the Locknor cutting, and a 

 clear cross-section (north and south) is to be observed at the entrance 

 into the village of Weston Street. The beds here have a considerable 

 thickness, and present the like general arrangement of horizontal 

 layers of sands and waterworn materials to be observed throughout. 

 With respect to composition, however, they present a peculiarity de- 

 serving of notice. Along the Albury Valley the proportion of chalk- 

 flints to other material derived from the subjacent sands is very con- 

 siderable ; but in the Weston-Street section we meet for the first time 

 with rounded and waterworn detritus of chalk. This material is not 

 mixed with the general mass of detritus, but occurs in layers : it 

 should be noticed that it is the upper portion of the gravel-beds which 

 is here exposed. It will be seen that this section occurs at the only 

 spot at which, by means of a transverse valley, there is a communica- 

 tion between the valley of the Tillingbourne stream and the base of 

 the North Down range. The gravel-beds are continued up the trans- 

 verse valley, but they gradually become more exclusively composed 

 of chalk : at one place a mass is to be seen composed of subangular 

 fragments, in which the parting seams alone are of sand, although 

 resting on the iron-stone beds of the lower greensand. It would 

 thus seem that during the accumulation of the higher gravel of the 

 Albury Valley, materials from the chalk-range were brought down from 

 time to time and interstratified with it, showing that this configura- 

 tion of a transverse depression in the lower greensand range must 

 have existed at the time of the arrangement of the uppermost gravels. 



The materials which compose these gravel-beds are derived from 

 the Cretaceous series, and are local, with the exception of the blocks 

 of greywether sandstone and breccia. These are much waterworn 

 and of considerable bulk ; they occur in every part of the area de- 

 scribed, not only in the open valley of the Pease-marsh, but along the 

 valley of the Tillingbourne, and are very common along the line of 

 Section, fig. 2. The supposition that this area was at one time an 

 enclosed bay will account well for the general arrangement of the 

 upper portion of the gravel mass, and some materials may have been 

 conveyed into such an area from without through the gorge in the 

 chalk-range. We have little warrant, however, for assuming that this 

 took place to any extent. The greywether blocks cannot be brought 

 under any such supposition ; their weight exceeds the moving power 

 of any limited area of water, and their presence there must be other- 

 wise accounted for. 



It has been shown that the gravel-beds supply evidence of move- 

 ments which must have taken place during their accumulation. It 

 will be seen by reference to fig. 2, and it has been already stated, that 

 the steep slope which the lower greensand presents at this place must 

 be of subsequent date to some portion of the gravel-beds. The chalk- 

 range supports up to its very edge thick beds of coarse gravel and 

 drifted sands, with great included blocks of greywether sandstone — in 

 all these respects corresponding with the gravel-beds of the Tilling- 

 bourne Valley below. Add to this the great fault which accompanies 

 the chalk-escarpment throughout, and we can require the admission, 



