File:The Quarterly journal of the Geological Society of London (13860132385).jpg

722
SEARLES V. WOOD ON THE NEWER
chalk on the beach, gave rise
to the irregular seams of loam
with land-shells, described by
Prof. Prestwich as overlying
and intermingled with these
blocks in the buried beaches of
Sangatte and Portland

and
the pressure of the floes re-
peated year after year probably
forced this accumulation more
thickly against the cliffs, so
that the upper part turned over
on itself; or it may have been
that floes thus driven on to the
shore became buried under loam
before they could thaw, and so
became part of the permanently
frozen soil, as is the case with
sheets of ancient flood-water
still remaining as ice in the
mudbanks of the Siberian
rivers from which the Mam-
moth carcasses have been de-
tached. If so, the thawing of
this ice after the glaciation
passed away would have let
down the loam &c. accumu-
lated over these floes and
around their edges, and so pos-
sibly have given rise to the
distorted appearance which the
accumulation exhibits in Mr.
Prestwich's cut of Portland
buried cliff.
By permission of the Coun-
cil, I also give here the late
Mr. Trimmer's cut of the brick-
field at Gaytonthorpe, in West
Norfolk.
The beds d, e, and /of Mr.
Trimmer's section are, he con-
sidered (and as I think also),
a freshwater continuation, at
proportionally higher level, of
the Nar brickearth

and
therefore, like the Avisford
sand, of the age of the Gyrena-
formation

and like that they
are overlain and penetrated by
the atmospheric formation of
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