Wood— On the East Essex Gravels. 401 



out in identically the same manner as those of the Lower Greensand 

 area, lying at the months of the trumpet opening of Snodland, and 

 are a repetition of them on a wider scale. They lie at the mouth of 

 a narrow and less deeply cut valley, that expands in a similar way 

 towards the south, near Yalding. The configuration points very 

 obviously to these gravels being the accumulation at the mouth of 

 the river - discharge after the Lower G-reensand area had been 

 elevated, and the sea reduced to the Weald Clay portions of the 

 Weald Yalley. From the ramifications of these gravels up the 

 courses of several streams, however, it seems probable that their 

 deposit continued after the reversal had begun, and the flow of the 

 drainage directed into its present course. 



The gravels and brick-earths grouped in the sections under the 

 symbols x5, x5^, x5^, etc., form a series of several gradations in age 

 when compared in position with each other, but none of them mark 

 any abrupt or decided horizon in the denudation. They generally 

 tail off on to the bare Chalk coimtry of the Downs, and seem to have 

 been accompanied by a continuous elevation, without any such change 

 as would give rise to a line of coast, sufficiently decided as to be now 

 recognizable ; but in the line of the scarp of the Chalk Downs we reach 

 a stage at which some very powerful cause must have come into play 

 so as to give rise to the sharply marked geographical feature which 

 this stage represents. I think that the state of things which can be 

 traced as having existed during the East Essex and Thames gravel 

 periods will throw light upon the origin of this marked feature. 



la division 5 of the Map I have, in order to render the argument 

 intelligible, represented what I conceive to be the terracing down of 

 the Thames and East Essex gravels, first to those of the Lower 

 Greensand terrace, and then to those of the Weald clay bottom, or in 

 other words the successive southerly advance of the coast line ; v/hiie 

 in division 3 of the Map I have delineated what the distribution of the 

 Thames and East Essex gravels indicates as the geographical outline 

 of that period.^ In it the sea occupies the Chalk country of the 

 South of England and the place were the Weald valley was after- 

 wards excavated.^ Now if we imagirie the upcast of the country, oc- 

 cupied now by the North Downs, and thence continuously across 

 into Northern France, to have succeeded this state of things, and to 

 have been accompanied by the formation of the series x5, xB' , x5" , 

 etc., we can realize that by it the sea of the South of England would 

 have shrunk mto a much smaller compass, and that its northern 

 limit was marked by the line of the North Downs, stretching across 

 the straits of Dover, and passing round the Bas Boulonnais. The 

 limit thus supposed is delineated in division 4 of Map, the North 



^ Restorations, such as are attempted in division 3 and 4, are regarded, and justly 

 so, with much suspicion. I have, only resorted here to that course in order to render 

 my views of the progress of the great post-glacial denudation intelligihle at a glance, 

 when pages of description would fail in that object. 



- The attenuation of the Chalk over the "Weald centre, and exposure of the 

 upper part of the beds beneath it at this time, as also the possible erosion of a part of 

 the Lower Tertiaries over the AVeald during some part of the Middle Tertiary period, 

 may be remembered here, for exactness sake, bat it is not material to the argument. 



VOL. III. — NO. XXVII. 26 



