PLTOCEITE PEEIOB IN ENGLAJJB. 511 



over the Chalky Clay (for there is generally none under it in this 

 region*), but we found no section to show this distinctly except at 

 Langton, near Wragby ; but the greater part of its range is where 

 none of this clay has been left. 



As this gravel extends north-westwards it rises gradually, so that in 

 Sheet 86 it crowns the escarpments at elevations exceeding 200 feet, 

 as described by Mr. Eome and myself in the 24th vol. of the Journal, 

 having there been called by us "Denudation gravel," under the 

 somewhat erroneous idea that it was connected with the denudation 

 of the Chalky Clay. Erom central Lincolnshire towards the Wash 

 the line of this gravel descends through the valley of the Witham 

 to very low elevations, so as to become undistinguishable from the 

 line of that surrounding the Wash, which is to be described in the 

 second part of this memoir. 



Within this circuit of gravel and above its line of elevation the 

 Chalky Clay everywhere, save where patches of gravel of the kind 

 described in Stage lY. occur, presents a naked surface, which could 

 not be the case if submergence in general had succeeded its deposi- 

 tion. 



A comparison of the elevation of the line of gravel e with that of 

 the gravel 5' should show the rise of England in the interval ; but 

 in the neighbourhood of the Chalky Clay, V caps only isolated hills, 

 the depth of water over which at the culmination of the submergence 

 we have nothing beyond the general increment of depth westwards and 

 southwards to show. Thus in fig. YII. e is less than 200 feet below h\ 

 but it is 260 feet below V on Danbury hill, which forms a promontory 

 on the north side of island Wo. 3, and is only 7 miles to the south- 

 west of fig. YII. At Ongar, e is scarcely 200 feet below the patch of 6* 

 which I found on Warley hill, while it is 265 below that on Hamp- 

 stead. If, however, we compare e at Ongar with V nearly 26 miles 

 due south of it, on Well Hill, against the unsuhmerged summits of 

 the chalk downs close adjacent, such as those at Knockholt, and 

 allow for the southerly increment which I have estimated at the 

 end of Stage II. as a little over 2*5 feet per mile, it gives a difference of 

 a trifle over 300 feet. If we compare e at Brickett Wood in the Colne 

 issue to the sea at 256 feet with 6' on the skirts of the Chilterns at 

 600 feet or thereabout, and allow for the westerly increment, we get a 

 difi^erence of about 250 ^eet ; but I have not been able to ascertain 

 with any precision the highest points reached by b' in that position, 

 and it may be more than 600 feet. Comparing e at 380 feet around 

 Hugby with the highest level at which gravel actually occurs on the 

 Cotteswolds, we get a difference of about 370 feet, but if the 

 westerly increment be taken into account, of 280 feet only. 



The further west, however, that we institute the comparison the 

 more do we approach the conditions of an increment of northerly 

 depression, such as is deduced in Stage II. between South Hants 



* At two or three places (Eanby, Market Stainton, and Brough-on-Bain) in 

 this neighbourhood there are patches of gravel which is either in or under the 

 Chalky Clay or is part of the first spoil produced by the washing-out of thQ 

 Bain-Steeping trough ; but the^ are of very small extent indeed, 



