82
CHELMSFORD WATER SUPPLY.
respect, bringing fresh material for examination from their burrows
daily. At the warren between Brook Farm and Seward's Hall the
peat is two feet thick, underlaid by shelly marl and clay to a depth of
some twelve or fourteen feet, when clean sand is found.
Eastward of this, near Hostages Farm—miscalled Horsteds on
the old Ordnance map used for the Geological Survey—another peaty
spot yields Helix lamellata, H. aculeata, H. rotundata with a very
tall spire, Zonites fulvus, Pupa ringens, Vertigo substriata, V. pusilla,
Acme lineata and others, now believed by Mr. French to be locally
extinct. Specimens have been submitted to Mr. J. W. Taylor, of
the Conchological Society.
H. lamellata is quoted as occurring in the North of England,
N. Wales and N. W. Scotland only, and Pupa ringens in the same
northern localities and in Guernsey.
The remainder of these geological rambles was chiefly devoted to
the determination on the new Ordnance maps, of the positions of
several of the artesian wells of which sections are recorded, and of
the level of the surface of the ground at those sites. This was done
at fourteen points, in Braintree, Bocking, Saling, Coggeshall, Kelve-
don, Southend, Prittlewell, Eastwood, Vange and Corringham ; and
the results will be noted in Mr. Whitaker's next series of Essex Well-
sections. The only other matter worth mentioning is that the Mal-
don sewer works have led to the discovery on Mr. Fitch's land of a
deposit of gravel a few feet under the alluvium—a boon to the en-
gineers, who wanted material for concrete, and also of course to the
proprietor. The extent of the deposit remains to be proved—it is
probably part of a wide spread of gravel, but higher at this point
than usual. It is charged with salt water, but not more, at any rate in
the upper part, than can be dealt with. The alluvial clay hereabouts
is much mottled with streaks of vivianite (blue phosphate of iron),
which appears to collect principally along the course of roots of
sedge and other vegetable matter, though often no such organic
cause is visible.
CHELMSFORD WATER SUPPLY.
By T. V. HOLMES, F.G.S., M.A.I. (President, Geologists Association).
ON March 31st, I accompanied Mr. T. Hay Wilson, E.F.C, on
a visit to the new water-works at Rainsford End, about half a
mile north-west of Chelmsford railway station. From the top of the