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THE ESSEX NATURALIST
An Essex Fossil Ziphoid Whale and its Implication
of Geographical Changes in Geological Times
By Harold E. P. Spencer, F.G.S.
A recent and most unusual find in a gravel pit at Ardleigh is
the middle portion of a rostral (snout) bone (Fig. 1) of a whale
which according to the interpretation of the circumstances in
which it was discovered, dates from about a quarter of a million
years ago.
Complete rostral bones of the ziphoid group of whales have
been known for many years from the Basement Bed of the Red
Crag, a marine shelly sand deposited over East Anglia some two
or three million years ago. The Red Crag occurs in north-east
Essex, notably in Walton-on-Naze cliff and is the product of a
sea at least one hundred and fifty feet deeper than the North
Sea,
Figure 1. Generalised cetacean skull with portion of rostrum found at
Ardleigh shaded.
The new fossil is remarkable for several reasons. Firstly, it
is believed that hitherto no remains of this type of whale have
been found in non-marine gravels of so late a date although there
are living representatives of the family, secondly the condition of
the bone is unmineralised and of a soft chalky consistency with
only the slightest traces of iron staining on the surface. This
fossil is comparable in condition with bones of elephants which
were discovered in the Brickearth of Wrabness about thirty years
ago, dating from the last interglacial, about one hundred thousand
years, when the evidence of fossil remains of the South European
Pond Tortoise (Emys orbicularis) suggests a Mediterranean type
of climate. The presence of very numerous shells of Corbicula
flumenalis (which is not now found living nearer than the River
Nile) at Brandon (Sudbury) and at Stutton in the brickearth also
support the view of a former warmer climate for this region.