ON THE GRAYS AND UPMINSTER RAILWAY. 145
which, from what we could learn about them, must have resembled
those revealed by the subsidences close to the Grays and Stifford
road.1 We were glad to learn that careful measurements of them
had been taken by one of the engineers of the line.
At c, the cutting shows the junction of the Chalk with the gravel,
sand, and sandy-loam which overlies both the Chalk and the
Tertiary rocks of the district, capping much of the higher ground
between Purfleet and East Tilbury. But while east of Grays and
Stifford it forms a broad continuous sheet, westward it appears
in a series of isolated patches. At c the Chalk may be seen south
of the hedge ranging east and west which is cut through by the
railway, the junction almost coinciding with the hedge line. The
position of a conspicuous band of black flint in the Chalk marks
the existence of gentle undulations in that formation, with a general
northern dip.
North of c the cutting speedily dies away, and the next sections
worth notice are a few yards northward of the next hedge cut
through at d. This cutting gradually deepens towards Back Lane,
and is for some distance 10 or 11 ft. in depth. At first as we
progress northward nothing appears but the plateau gravel, which
is of a reddish colour, with stones mostly of a rather small size.
They appear to consist almost entirely of flint, though I found one
of quartz, almost as large as a hen's egg. Possibly we might have
seen others had time permitted a longer search. About 120 yards
from Back Lane Chalk began to appear here and there towards the
bottom of the cutting in an irregular way, and continued to show
itself as far as the bridge at Back Lane though not beyond it.
Besides the solid Chalk near the bottom of the cutting, there were
many fragments of it much higher up mixed with pebbles, clay, or
loam, in such a way as to suggest the possible action of ice, in
addition to that of pipe-making rain-water.
Perhaps, indeed, what we saw might, in the case of this old
1 See Essex Naturalist, vol. iii., p. 183,
L