XXVI 
PROCEEDINGS OE THE 
Field Meeting, 30th June, 1888. 
RICKMANSWORTH AND CHORLEY WOOD. 
The last field meeting of the season was held in the neighbour¬ 
hood of Rickmansworth, in conjunction with the Geologists’ Asso¬ 
ciation of London, and under the direction of Mr. Hopkinson. 
Its chief object was to examine sections of the Upper Chalk exposed 
in cuttings of the extension of the Metropolitan Railway beyond 
Rickmansworth now in progress, sections of the London Clay and 
"Woolwich and Reading Beds along the same line of railway between 
Pinner and Rickmansworth having been examined on a former 
occasion.* 
The route taken was through Rickmansworth and Loudwater 
Parks in the valley of the Chess, over the hill on the south-west 
into the dry valley which extends from Loudhams, about midway 
between Chenies and Amersham, to the valley of the Chess at 
Rickmansworth, and then up the next hill to Chorlev Wood Kiln. 
This is not now a brickfield, but part of the garden of a private 
house, the occupier of which allowed the members to inspect the 
section exposed. It is nearly on the edge of an outlier of the 
Reading Beds of about a square mile in extent, conspicuous from 
the valley below by forming a well-wooded eminence, and its chief 
interest is in showing an unusual development of the bottom-bed 
of flint-pebbles. This bed is 12 feet in thickness, and the pebbles, 
some of which are very large and might almost be called boulders, 
are closely packed together, only the interstices left by their 
spherical shape being filled up with sand. It is this bed which, 
somewhat similarly developed, forms, in the neighbourhood of 
Radlett, the well-known Hertfordshire conglomerate. 
The following is Mr. Whitaker’s description of the Reading 
Beds seen in this section: j-— 
Plastic clay {paving clay). 
Clayey sand, brown and light-coloured, 1J feet. 
Red-mottled plastic clay ( tile-clay). 
Bluish-grey sandy clay {devil). 
Green sandy clay {fire-earth), with an irregular line of ironstone nodules 
{red-knob) ; below which it is more sandy, and passes into 
Green sand. 
Bottom-bed.—Flint-pebbles, some very large, in sand, greenish towards the 
top, brown and light-coloured lower down ; about 12 feet. 
The junction with the Chalk was seen in a pit close by; and 
at a little distance to the west there is a swallow-hole formed by 
water falling as rain on the Reading Beds and flowing over or 
percolating through them to the edge of the Chalk, on meeting 
which it sinks through and dissolves it. This swallow-hole, it 
was found, now holds water, having evidently been artificially 
plugged by puddling in order to form a pond. 
A footpath was then taken down to Chorley "Wood Bottom, by 
which the Common was reached, and the return walk to Rick- 
* See ‘ Transactions,’ Yol. IV, p. xlvii. 
f ‘ Geology of London,’ p. 193. 
