Journal of Proceedings. xiii
Saturday, May 14th, 1881.—Field Meeting.
Excursion to Grays Thurrock, Essex. Conductors : Professor John
Morris, M.A., F.G.S., and Henry Walker, Esq., F.G.S.
[For the Geological portions of this report the Editor is indebted to the
kindness of Mr. Walker, who supplied the admirable resume embodied
in the following pages.]
This being an excursion in conjunction with the Geologists' Association,
the members of the two Societies assembled in very considerable numbers,
leaving Fenchurch Street Station by the 2.25 p.m. train. The route for
almost the entire distance lies across the gravel and alluvial flats of the
Thames Valley. The wide and shallow tributary valleys of the Lea and
the Hoding, as they were successively passed, were well seen. During the
remainder of the journey the nearer features southwards are the levies
confining the River Thames within its modern artificial channel, whilst
beyond is seen the bold and natural horizon formed by the chain of hills
stretching from Greenwich to Erith, the southern limit of the valley along
that line. On nearing Purfleet, the western outcrop of the small area of
chalk which is found in South Essex begins to be visible. On nearing the
station, and looking to the left-hand side of the railway, an old chalk-pit,
abandoned now to the botanist and entomologist, reveals both the chalk
and the Thanet sand, the latter capping an isolated mass of the former.
Past the station the bare sides of the great conical mound of Thanet
sand, having a high angle of rest, and being a very conspicuous object
from the Erith side of the river, is close at hand. The remaining three
or four miles of the journey lie along the West Thurrock Marshes, but on
the left the presence of the chalk skirting the railway is told by its
characteristic contours.
Alighting at Grays, the party received some notable reinforcements, and
the united forces, considerably exceeding one hundred in number, were
conducted by Mr. Walker to the high road leading to Stifford. Here the
extent and position of the three southern chalk-pits are well seen ; the
East Pit; the Central Pit (appropriated for the manufacture of whitening);
and the Western Pit, occupied by the South Essex Waterworks Company.
Attention was called to the flooded condition of the Eastern Pit, the floor
having been worked down to the level of the springs, and the pumping
being temporarily suspended. The sides show the green-flint bed lying on
the surface of the chalk, and the Thanet sand above. The islands below,
overgrown at the surface with vegetation, but revealing on their bare
sides a sharp dip of their component strata, were here the subject of some
cautionary remarks; their real character as spoil-heaps, or "tips" of
Thanet sand and gravel, has not always been recognised, even by geological
visitors. A descent to the central pit was then commenced. On the way
one of the Greywethers or Sarsen-stones, for which Grays has long been
notable, was found lying on the unworked surface of the chalk, at a spot