356 PLEISTOCENE GEOLOGY OF THE THAMES VALLEY.
collection). Lately, however, it has been found in a Holocene
rainwash at Reigate, and now that it has been proved to occur
in the Pleistocene it must be considered an ancient inhabitant
and not a recent introduction, a conclusion which is in accord-
ance with its discontinuous distribution in England.
Clausilia bidentata, Ström. Several fragments. Hitherto
unrecorded from Grays.
Succinea putris, Linn. Recorded by the late Professor
John Morris.
Succinea elegans, Risso. Several examples. A new
record for Grays,
Carychium minimum, Müll. Two imperfect examples,
thus confirming the record of this species by Prof. Morris. In
the Pleistocene of the Thames Valley it is only known from N.E.
London, the Admiralty section and Ilford.
Ancylus fluviatilis, Müll. Common.
Velletia lacustris, Müll. Common. (This species is
generally known as V. lacustris, Linn., but it is not Linne's
species which is the shell known as Ancylus fluviatilis, Müll.
Hence to avoid confusion it is better to ignore Linne's name).
Limnaea auricularia, Linn. A single example.
Limnaea pereger, Müll. Common.
Limnaea palustris, Müll. Common.
Limnaea truncatula, Müll. Common.
Limnaea stagnalis, Linn. A single apical fragment
only. Recorded by S. W. Wood, but hitherto no example
known.
Planorbis corneus, Linn. Recorded by S. V. Wood.
Planorbis albus, Müll. Common.
Planorbis glaber, Jeff. Two examples, thus enabling us
to confirm S. V. Wood's record.
Planorbis nautileus, Linn. Recorded by S. V. Wood.
Planorbis carinatus, Müll. Listed by Prof. Morris.
Perhaps an error for the next species.
Planorbis marginatus, Drap. Several examples.