264 J. E. Marr — Glacial Deposits. 



Very different is the condition of tlie overlying drifts. Before 

 proceeding to describe them, I may refer to the section fig. 17 of the 

 Geological Survey Memoir on the Geology of N.W. Essex, etc. 

 This section is described by Mr. Whitaker as occurring on the foot- 

 path to Chilton ; it would therefore lie somewhere to the east of the 

 section now under consideration. The structure of the Crag ridge 

 and the disposition of the overlying drifts would seem to indicate 

 that there was a continuation of the ridge now visible in Mr. 

 Green's pit, in which case the ridge probably has a general E. — W. 

 direction, as may indeed be gathered from an examination of Mr. 

 Green's pit itself. The section figured by Mr. Whitaker is now 

 destroyed. 



The ridge in Mr. Green's pit increases in height and breadth 

 towards the west, as shown by comparing a photograph which I 

 caused to be taken at the end of the year 1886 with the present 

 exposure, several feet of the face of the cliff having been cut away 

 in the interval. 



The description of the drift deposits of this pit is not quite so easy 

 as that of the older formations. Mr. Whitaker describes the Boulder- 

 clay in the pit on the footpath to Chilton as filling up a hollow in 

 the gravel, but the section as drawn by him is explicable also upon 

 the supposition that the gravel fills up a hollow in the Boulder-clay. 

 In the case of Mr. Green's pit, I came to the conclusion that the 

 latter was the case, and have therefore taken the Boulder-clay as the 

 deposit which would under ordinary circumstances be the lowest. 

 This may be the case here, even if the Boulder-clay in the pit on 

 the footpath to Chilton is above the gravel, as Mr. Whitaker shows 

 that there are two Boulder-clays in the area. The succession, as 

 gathered from a careful examination of Mr. Green's pit, appears to be 

 as follows : — 



1. Boulder-clay. 



2. Coarse sand and gravel. 



3. Fine loam. 



And this is the order in which I shall describe the accumulations. 



The Boulder-clay 1 — Figs. 1 and 2 — consists of a very stiff brown 

 or leaden-blue clay, having at the south end of the pit a series of 

 wavy divisional planes. Besides this, it in places contains very 

 close-set divisional planes, reminding one strongly of the " fluxion- 

 structure " of igneous rocks. Along some of these carbonate of lime 

 has collected, giving the deposit here and there a marked banded 

 appearance. The deposit is full of boulders, mostly small, the 

 greater number being of white chalk (often striated) and flint, but 

 blocks of sandstone also occur, especially a port-wine red sandstone. 

 In the north part of the pit a small patch of Boulder-clay occurs in a 

 depression of the Thanet Sands, but separated from them by gravel. 

 This clay forms a horizontal tongue a yard or two long, and 2 ft. 

 Gin. high. At the bottom of the clay, and resting on the gravel, 

 are patches of red clay, clayey green sand, and a mixture of the two, 

 evidently torn off from the rocks close by. The Boulder-clay 

 probably owes its position here to a fault which appears to run 



