352
THE ESSEX NATURALIST
recorded in 1795 by John Frere who described the large numbers
of flint artifacts discovered there as the implements "of men who
had not the use of metal". There is every reason to suppose the
Hoxne and Mistley deposits do belong to the same period of
geological and geographical development due to changes of sea
level.
It is generally assumed that during a glacial period the sea
level is lowered in proportion to the amount of water converted
into ice, conversely interglacials are periods of high sea level. In
East Anglia no raised beaches of the earlier interglacials later than
the 150 feet Red Crag beach at Battisford, Suffolk, seem to have
survived the destructive action of subsequent ice sheets. Most of
the uppermost deposits on high ground are of glacial origin, either
chalky boulder clays or outwash sands and gravels deposited by
meltwater as the ice fronts receded. These deposits conceal the
true character of underlying beds which are all too often otherwise
inaccessible owing to a high water table (see fig. 2).
The facts so far indicated show changes of sea level have
occurred and recurred over a relatively short period of geological
time and were preceeded by a similar series of changes, The
Hoxnian epoch followed the Lowestoft glaciation and was suc-
ceeded by the Gipping ice sheet both of which extended as far
south as the Thames valley. Boulder clays or tills are deposited
directly by melting ice and both Lowestoft and Gipping tills con-
tain a great amount of derived chalk indicative of much destruc-
tion of that formation, some 250 feet of chalk is missing at Ipswich.
Outlying remnants of these glacial deposits occur in S.E. Suffolk
but appear to be very rare or absent in N.E. Essex which argues
for the great amount of denudation which effected their removal
as is patently indicated by the present topography at Hoxne. The
upper part of the section at the Ardleigh gravel workings seems
to be glacial outwash gravel without any boulder clay (till) to
prove from which ice it resulted. It is unfortunate the lower part
of the section is below the water table and it is not possible to
examine the lower gravel. One feature has been observed, how-
ever, which appears to establish a lower limit to the glacial gravel,
this is a zone of disturbed deposit caused when conditions of
freezing and thawing caused the soil to flow, crumpling the strata
(see fig. 2). The deposit below this level must inevitably belong
to an earlier epoch than the upper part, from which the fossil
whale snout presumably came.
Whales are marine creatures and their remains are not nor-
mally found in inland deposits; the occasional bones found are
generally associated with the former whale fishery. As recently
as 1816 a large whale was stranded in the Orwell Estuary and
latterly schools of smaller species have committed suicide on the
shores of these islands. It is reasonable to assume similar occur-
rences have taken place for many thousands of years and did so
when our coastlines were more restricted than at present by
reason of a higher sea level. In such circumstances our east coast