4 THE NEW RAILWAY BETWEEN UPMINSTER AND ROMFORD.
Romford last March, Mr. H. B. Woodward stated that, having seen
this section, he thought it afforded a better exposure of Boulder
Clay than he had elsewhere seen in Essex during two years' work on
the Geological Survey. The greatest thickness measured was fifteen
feet. When this cutting was visited by the Geologists' Association
on March 5th, 1892, Mr. Robertson, the engineer of the line, very
kindly exhibited a collection of the most interesting specimens
obtained from the Boulder Clay. They included many lumps of
Kimmeridge Clay, some examples of Gryphaea dilatata from the
Oxford Clay, and a vertebra which had been determined by Prof.
Seeley as plesiosaurian. Some small shells in a glacially-scratched
lump of bituminous shale belonging to the Kimmeridge Clay were
identified by Mr. H. B. Woodward as Lucina minuscula.
A space of about 250 yards, without any section, intervenes
between the cutting just described and that on both sides of the
road at Butts Green. Towards the eastern end of the Butts Green
cutting only sand and gravel could be seen, the greatest thickness
shown being about ten feet. But near the road five or six feet of
London Clay appeared beneath eight or nine feet of sand and
gravel, and London Clay was more or less visible at the bottom of
the cutting as far as it extended in a westerly direction.
West of the stream, which crosses the railway about 500 yards
from Butts Green, there are cuttings as far as the junction of the
new railway with the Great Eastern line, about half a mile east of
Romford Station, Close to this junction I have seen London Clay,
as well as the overlying sand, gravel or loam ; but nearer the Brent-
wood Road a permanent wetness in the sand and gravel, at a depth
of about ten feet, afforded the only sign of the proximity of clay.
In my description, already referred to, in The Essex
Naturalist, of the sections between Grays and Stifford, I some-
what rashly remarked that having arrived at the London Clay on the
northern flank of the Mardyke valley, we might be sure that the
sections seen southward were those of the most geologically interest-
ing part of the line, the rest of it being likely to show nothing but
London Clay, with a capping of gravel or loam. Fortunately, as the
Hornchurch cutting demonstrates, my prediction was a mistake.
On the other hand, my remarks deprecating the assumption that
signs of ice-action of some kind necessarily imply that beds showing
it belong to the Glacial Period (in forgetfulness of the fact that ice
has been a geological agent from a very early period, and is one now),