THE DISTRICT AROUND CHELMSFORD.
177
Mr. Woodward, in forwarding me the list of species, and referring
to this deposit and to another, one and a half miles off, at Chignal,2
says:—
" Broadly speaking, these two deposits may be held to be of the same age as
the celebrated one at Copford, in which all the species named above occur.3
Physa hypnorum does not occur in the Chignal list.
From the scarcity of fluviatile forms it may fairly be argued that the spot from
which these shells were obtained was formerly marshy ground by the side of the
present stream, which, at flood time, swept over the place, leaving behind, when
it retired, the shells which it had brought down on its way from the high ground
to mingle with the other forms, such as Carychium mininum and Vertigo pygmaea,
that dwelt on the spot."
Relics of pre-historic man in the shape of stone implements are
not abundant in the district, although by no means altogether absent
A very beautiful spear-head, found in the gravel pit just outside
Chelmsford, on the Roxwell Road, has been described by Mr. Henry
Corder, in the "Trans : of the Essex Field Club," (vol. ii, pp. 29—31)
and is now in his possession. I have myself picked up several imple-
ments, the use of which seems rather doubtful, but bearing undoubted
traces of artificial shaping. These were found on the surface of an
arable field in Roxwell parish.
Many relics of Saxon and Roman inhabitants occur in the neigh-
bourhood, but descriptions of these would hardly come under the
head of geology.
Discussion.
At the reading of the above paper at the meeting at Chelmsford, on February
9th, 1889, Mr. W. H. Dalton, F.G.S., expressed regret for his imperfect know-
ledge of the geology of Chelmsford, his work on the Geological Survey of the
district having consisted of such part of it as is comprised in Sheet 47 of the one
inch map, and not coming nearer to Chelmsford than Boreham, Broomfield, and
the Chignalls. There were many problems still to be worked out, and he looked
for their solution to the band of able and energetic geologists which the Club had
in a manner created, and was so sedulously fostering.
The sub-division of the Boulder Clay into a lower (blue) and an upper (white)
bed in the neighbourhood of Roxwell and the Chignalls was unquestionable, and
the parting of sand and gravel, sometimes several feet in thickness, constitutes a
source of water supply to some of the wells. Possibly its outcrop might be traced
by ponds and springs, but its presence was not known at the time of the Geological
Survey of the district. The difference between the beds could not certainly be
attributed to recent atmospheric action, but denoted a variation of the source of
the glacial detritus. A study of the nature of the stones in the lower and upper
parts of the clay might elucidate this. Amongst other unsolved problems, as
2 An account of the Chignal deposit has been published by Mr. Miller Christy in the Essex
Naturalist, ante pp. 1—10.
3 J. Brown, "Quart: Journ : Geol: Soc :" viii (1852), p. 189.