ON A RECENT SUBSIDENCE AT MUCKING, ESSEX. 243
These depressions were in a line from 400 to 800 yards westward
of the recent subsidence, and their similarity in shape and
breadth, though their sides were sloped, certainly makes this
view highly probable, The only other explanation of their
existence would be to consider them as simply disused gravel-
pits. But their uniformity of shape, and distribution along a
line across a single field, makes any supposition of this kind
improbable in the extreme. For there is plenty of surface gravel
in the fields around all the depressions mentioned, and many
Section No. 1—Mucking Subsidence (1906). No. 2—Blackheath Subsidences
(April, l978, and November, 1880). Both the latter were practically identical
in size and shape.
gravel pits in all directions. There is no gravel at the surface of
the recent subsidence, simply because it is at the head of a slight
valley ranging southward from the plateau of old Thames gravel
in which these (in all probability) older subsidences occurred.
About a week later, wishing to examine the country west of
these depressions, I noticed a shallower hollow of similar shape,
on the southern side of the footpath leading to Orsett, in the
field north-west of the Cock Inn,
It seems necessary at this point to introduce a brief account
of the geological structure of this district, by which I mean that