﻿1851.] AUSTEN ON THE GUILDFORD GRAVEL BEDS. 281 



slopes, is occupied by beds of stratified sand and gravel, which sug- 

 gest the speculation that they have been spread out uniformly by the 

 action of a mass of water, which at some time occupied the whole of 

 the valley, and that a central portion of the accumulation has been 

 since removed. 



In the Pease-marsh portion of the valley, as on both sides of the 

 Portsmouth road, the gravel- beds rest on Weald-clay ; in other places 

 they are on Neocomian beds, and towards the edges of the denudation 

 they are on portions of the Lower Greensands. These beds, and 

 throughout their whole thickness, exhibit the ordinary and unmis- 

 takeable characters belonging to such as have been arranged beneath 

 water of no great depth ; — the materials are coarse and waterworn, 

 are spread out horizontally in successive seams or layers, and, what 

 is of the greatest importance as evidence of a gradual process of ac- 

 cumulation, is the circumstance that interposed beds of sand occur 

 throughout, having a diagonal arrangement. 



The thickness of this accumulation depends on the inequalities of 

 the surface on which it rests, and varies from 3 to 25 feet ; yet 

 there is a general order of succession to be observed, as follows :— 



1 . Black vegetable earth ; peat ; bog-iron-ore. 



2. White and grey marls. 



3. Brown and red clay. 



J 4. Fine gravel and sands. 



\ 5. Coarser gravel and drifted sands (diagonal) ; blocks of Sars- 

 den stone ; teeth and tusks of elephants, single and rolled. 



6. Peaty mud, with wood; (local). 



It must be understood that the upper part (1, 2) of this series is 

 local ; the lower (3, 4, 5), however, is constant. 



Throughout the whole of this area, which is comprised within the 

 Lower Greensand ranges, the material of the gravel is of rounded or 

 subangular chalk-flints. With it is iron-stone, chert, and Bargate 

 sandstone. There is also in places much small shingle of quartz and 

 lydian-stone, which has been derived from the conglomerate-beds of 

 the lower greensand. There are also occasionally large rounded 

 blocks of greywether sandstone, breccia, and pudding-stone from the 

 lower tertiary series. In the distribution of these materials, the prin- 

 cipal mass of pure flint-gravel will be found opposite to, or in the 

 line of the gorge at Guildford, as along the line of the railway-em- 

 bankment, and on the Pease-marsh : along the several branches of 

 the valley, the proportion of materials from the lower greensand in- 

 creases : near Godalming, in the last railway-cutting, some rearranged 

 sands had so completely the look of undisturbed greensand, that, but 

 for the mammalian remains, they could not have been referred to the 

 gravel. From this short account of the position and arrangement of 

 the gravel-beds in the Guildford Valley, we may deduce some general 

 considerations as to one stage of a former condition. 



It is absolutely necessary towards the production of strata or beds 

 with diagonal lamination, that there should be an onward movement 



