210 THE ESSEX FIELD CLUB.
able to see little more than the top re-arranged gravel that is now worked at
Langtons on the eastern side of the road.
Mr. Woodward remarked that the origin of the pebble beds was of some
interest, for they consisted of marine shingle derived from the waste of Chalk
cliffs, that probably existed in Bagshot times, far away to the west or north-west of
the district. They showed, at any rate, as did other Eocene pebble beds, that the
Chalk must have been upheaved locally so as to form land during Eocene times,
although, as pointed out by Mr. Whitaker, over large areas the Chalk beneath the
Tertiary strata presents no signs of disturbance, the bedding of each being
conformable.
Mr. Monckton differed from Mr. Woodward as to the marine origin of these
Warley pebble beds, and also as to their being of Bagshot age. He believed that
they are mainly debris from Bagshot, or more recent pebble beds, which have been
collected in their present position by various denuding agents. The place at which
they are now seen formed, at the time of their deposition, the bottom of a valley
which, in course of time, and in the further progress of denudation, has become
the top of a hill, the mass of pebbles having served to protect the sandy beds on
which they rest. In support of his opinion he pointed out the irregular manner
in which the gravel has been deposited, and the presence of subangular flints,
several of which were found by Mr. Herries at a considerable depth below the
surface, and in that part which Mr. Woodward considered to be undisturbed.
The question, therefore, of the occurrence of Bagshot pebble beds in situ was left
undecided.
It should, moreover, be mentioned that in 1868 Mr. Wood suggested that the
Pebble beds might be Pliocene; at the same time he maintained that they were
quite distinct from the "Gravel of the Higher Plain" (Pebble Gravel).3 Again,
in 1880, Mr. Wood spoke of the beds as "either of Bagshot or more probably of
Diestian age." 4 He appears always to have looked on them as marine.
The sections at present show, according to Mr. Woodward, mainly the re-
assorted surface of the Bagshot pebble beds, a feature recognized during the
Geological Survey,5 although, as he remarked, it was not found possible to separate
on the map the disturbed from the undisturbed pebble beds in the areas where
the two occurred in conjunction.
Mr. J. T. Powell acted as botanist, but no plants of special note were observed
during the afternoon. Warley Common formerly had a reputation for interesting
plants, and it is given as a station very frequently in Gibson's "Flora of Essex."
In Daniel Cooper's "Flora Metropolitana" (1836) a list of about fifty plants is given
on the authority of Dr. AEneas MacIntyre, and in Dr. E. C. De Crespigny's "New
London Flora" (1877), a more extended catalogue is given, and the following
general remarks about the botanical characteristics of the Common are made
which deserve quotation :—
" Warley Common, like many other localities about London, has undergone
alteration of late years ; much of the bordering forest-land has been enclosed, and
a gravelly pasture fronting the depot barracks has been converted into a drilling
ground for the recruits. The common is about one hundred acres in extent, its
longest diameter north to south. The woods, which surround it on all sides but
the south, are mostly of oak, birch and hornbeam, with an undergrowth of bracken,
hazel, thorn, &c. In the centre, and opposite to the entrance to the grounds
3 Quart: Journ : Geol : Soc :, vol. xxiv, pp. 465, 466.
4 Ibid., vol. xxxvi, p. 473.
5 "Geology of the London Basin," p. 323.