214 THE POST-PLIOCENE NON-MARINE MOLLUSCA
Valvata piscinalis (Müll.)
,, cristata Müll.
Bythinia tentaculata (Linn.)
Corbicula fluminalis (Müll.)
Anodonta cygnaea (Linn.)
Sphaerium corneum (Linn.)
Pisidium amnicum (Müll.)
„ astartoides (Sandb.)
,, pusillum (Gmel.)
From the adjacent Uphall Pit forty-six species have been
obtained, for in addition to the thirty-nine species recorded by
J. P. Johnson and G. White in the last part of the Essex
Naturalist (ante pp. 157-160), seven other forms are known,
viz. :—
Hygromia hispida (Linn.)
Helicigona arbustorum (Linn.)
Succinea putris (Linn.)
Planorbis albus (Müll.)
,, lineatus (Walk.)
Bythinia leachii (Shep.)
Unio pictorum (Linn.)
The two lists thus shewing a total of fifty-seven species,
being the largest number known from any Pleistocene or Holo-
cene deposit with the exception of Copford and Barnwell. It is
indeed worthy of note that in 1890, when the shells from Ilford
were first listed by one of us,2 only twenty species were known,
though ten others were listed on the authority of the various
recorders. In 1897, as a result of Dr. Corner's labours, we were
able to list thirty-seven forms from known specimens and nine on
authority, whilst the last three years' work of Mr. Hinton, Mr.
Johnston, and Mr. White has raised the total to fifty-seven known
species. There still remain three records to be confirmed, viz.:—
Pyramidula ruderata (Stud.)
Vitrea fulva (Müll.)
Planorbis corneus (Linn.)
Of these there is one form which we strongly desire to be
confirmed, Pyramidula ruderata. The record is on the authority
of Dr. J. Gwyn Jeffreys, who in 1869, during the discussion
following a paper by Professor W. Boyd Dawkins "On the
2 B. B. Woodward.—"On the Pleistocene Non-Marine Mollusca of the London
District," Proc. Geol. Assoc., vol, xi., pp. 335-388.