THE POST-PLIOCENE NON-MARINE MOLLUSCA OF ESSEX. 103
was picked off the stuff that had been thrown down from the
section and must have come from one of the sandy patches
mentioned. The other shells are :—
Pupa muscorum Planorbis spirobis
Limnaea pereger ,, marginatus
Planorbis corneus? Bythinia tentaculata.
With the exception of H. itala, all the species are found at
Grays, and as they come from the same series of beds they are
so included in the table.
ILFORD.
To Professor J. Morris we are indebted for the first list from
this locality. This was in 1838, and contained ten names (5).
In 1867, Professor Boyd Dawkins quoted twenty species as
occurring (12), and the list was further extended in 1869 by Mr.
A. Tylor on the authority of Mr. Alfred Bell (14) ; while in 1890
Mr. B. B. Woodward listed twenty species from existing speci-
mens and ten on the authority of the several recorders (31). It
must always be a matter of regret that a small portion of the
energy which was devoted to obtaining the Vertebrate remains
was not directed to the Mollusca, especially since the shell-beds
are now worked away. That the shells were formerly extremely
common there is no reason to doubt, as Dr. Cotton remarked in
1847, "The two genera of shells of which hundreds may often be
obtained at one visit are Helix and Cyrena, but Unio and Planorbis
are not uncommon, and Ancylus, Succinea, Valvata, Limnaeus,
Cyclas, and Paludina have been discovered. They are chiefly
seen in the layers of sand upon which the brick-earth reposes
and beneath the bones, but are sometimes intermixed with them,
and have been found even within the cavities of the bones.
They appear to be partial in their distribution, and are not met
with in the former cutting (i.e., north side of London Road—
Curtis' Brickfield) (9). For some years past Dr. Frank Corner
has assiduously collected at Ilford, and he most generously
placed his collection at our service. Mr. W. M. Webb has also
a few specimens, one of which, Succinea elegans, is a new record.
Dr. Corner's collection has enabled us to materially swell the
list, no less than ten species being new, viz. :—
Helicigona arbustorum Planorbis vortex
Helicella virgata ,, spirobis
Pupa cylindracea ,, contortus
Valvata cristata Pisidium astartoides
Planorbis glaber ,, pusillum.