274
ON SOME GEOLOGICAL SECTIONS AT
WITHAM, ESSEX.
By J. FRENCH.
IN making the new railway station at Witham some Glacial
beds have been exposed, which possess rather more than
ordinary interest, as I shall endeavour to show.
The first section to which I would direct attention is that
made on the west side of the cutting by the cross-over bridge at
the station. This section, which I roughly estimate at 18 feet,
shows at the basement about 3 feet of Westleton Sand and
Gravel, succeeded by about 13 feet of Glacial-gravel, and this is
overlaid by about 2 feet of Boulder-clay remainae and surface
soil. The quality of the members is very pronounced. The
Westleton-sand is unmistakeable. The Middle-glacial Gravel
is also a typical specimen and the Boulder-clay remainae,
although its calcareous elements have been extracted, is also an
unmistakeable element. In a long search for a section showing
these three members in juxtaposition I have hitherto been
unsuccessful. When the railway was made from Witham to
Braintree in 1849, Professor Prestwich saw and figured such an
exposure1, but all his exposures have long since been covered up.
His section compares very well with the one above described.
In both the Boulder-clay is indented into the Glacial-gravel,
whilst the Glacial-gravel below is very much mixed up with the
Westleton-bed. The exact line of demarcation cannot be made
out. Beyond a certain place we can safely assign all to the
"Middle-glacial," and below another certain place we can assign
all to the "Westleton."
The other exposure is on the east side of the railway cutting
opposite to the other. It is interesting as showing a rather con-
siderable quantity of Post-glacial Gravel resting ou Middle-
glacial Gravel, and with no trace of intervening Boulder-clay.
There is a very large funnel-shaped depression in the lower
member, say, 20 feet wide by 15 feet deep, filled with the Post-
glacial Gravel and loose earth. This shades off on either side
into a uniform covering of about three feet of the same material
which, so far as it is exposed, shows minor kind of "pot-holes"
at intervals. This points to a denudation of the Boulder-clay,
probably of the River-drift period. I find by reference to the
1 "On the relation of the Westleton-Beds, etc." Quar. Journ. Geol. Soc., February, 1908.