EASTERN BRITISH PLIOCENES.
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characteristic of the lower Gedgravian Crag, and unknown in
the later Red Crag beds.
For example, such shells as the Siphos, Latirus costifer,
Murex tortuosus, Nassa reticosa, and other common Red Crag
forms, all rare or almost unknown in the Gedgravian Series,
point I think to the intermediate facies of the Fauna—so far as I
can ascertain, the characteristic Red Crag shell, Neptunea con-
traria, has never been found in this zone, nor in any of the beds I
propose associating with it.
The same conditions prevail at Ramsholt. Mr. Canham's
collection, now at Ipswich, from a pit or section long closed,
revealed a similar grouping. The shells, like those at Boyton,
are in beautiful preservation, some are barely tinged with a
pale red, others like the fine Trochus conuloides, are full of a
dark chocolate matrix. Purpura tetragona occurs here for the
first time in its history.
On the opposite or right bank of the River Deben, at Waldring-
field, a bed of fine sand, 11/2 to 2 feet thick, was present below the
Coprolite beds full of double bivalves. Here Gastrana laminosa,
a not very common Gedgravian shell, abounded with Astarte
omalii, Cardita senilis, Mya truncata and Pholas (in situ), and
Tellina obliqua, a very large proportion of the double bivalves
given in Prestwich's lists (op. cit., p. 480) on my authority coming
from here. Lumps of indurated clay, full of small shells, Sax-
icava, Kellia, Scintilla modiolana and Tapes, were common.
I am further disposed to refer to this zone, the well-known, if
seldom seen, basement bed at Walton-on-the-Naze, which rests
directly upon the London Clay, usually considered as the oldest
of the Red Crag beds. This is full of double Pedunculi, Solens
with easily separated valves and others not occurring higher
in the section in this condition. As at Boyton, a slight trace
of the remanie or derivative items is present; small Coprolites,
rolled bone, box stones, also a few pieces of bone and teeth,
more or less broken, of Rhinoceros and Mastodon. A perfect
and well preserved snout of a Ziphoid whale, Z. longirostris, is
in Mr. Harmer's collection from this bed.
It would thus appear that we have between the Gedgravian
and Red Crag Series a zonal area defined by the peculiar
fauna, the abundance of double bivalves, the quiescent condi-
tion under which it flourished being indicated by the unrolled