ALLUVIUM AT WALTHAMSTOW, ESSEX.
15
The band formulae of the examples of Helix nemoralis are:—
In the Lockwood reservoir at one spot close to the main
stream was a sandy deposit, obviously quite modern, containing
a large number of non-marine shells, as well as examples of
Ostrea edulis and Buccinum undatum. We were informed by Mr.
Traill that a mill formerly stood near this spot. The species
found are thirty-six in number, viz:—
Pyramidula rotundata (Mull.)
Helicella cantiana (Mull.)
Hygromia hispida (Linn.)
Vallonia pulchella (Mull.)
Helicigona arbustorum (Linn.)
Helix nemoralis, Linn.
Succinea putris (Linn.)
,, elegans, Risso.
Ancylus fluviatilis (Mull.)
Limnaea pereger (Mull.)
,, auricularia (Linn.)
„ truncatula (Mull.)
„ palustris (Mull.)
,, stagnalis (Linn.)
Planorbis corneus (Linn.)
,, albus, Mull.
,, stroemii, West.
,, carinatus (Mull.)
Planorbis marginatus, Drap.
„ nautileus (Linn.)
,, vortex (Linn.)
„ contortus (Linn.)
Physa fontinalis (Linn.)
Bithynia tentaculata (Linn.)
„ leachii (Shepp.)
Vivipara vivipara (Linn.)
Valvata piscinalis (Mull.)
Neritina fluviatilis (Linn.)
Unio tumidus, Retz.
,, pictorum (Linn.)
Anodonta cygnaea (Linn.)
Sphaerium rivicola (Leach.)
,, corneum (Linn.)
,, lacustre (Mull.)
Pisidium amnicum (Mull.)
,, supinum (A. Schm.)
The band formulae of the examples of Helix nemoralis are
Many other samples of modern deposits from other spots
were examined, but they yielded no fresh species.
As we have already stated, far more attention was paid to the
Shell-marl than to the other deposits. The patches varied in