THE
ESSEX NATURALIST:
BEING THE
Journal of the Essex Field Club
FOR 1893.
THE NEW RAILWAY BETWEEN UPMINSTER
AND ROMFORD.
BOULDER CLAY BENEATH OLD RIVER GRAVEL AT
HORNCHURCH. CONCLUSIONS THEREFROM.1
By T. V. HOLMES, F.G.S., M.A.I., etc.
[Read February 21st, 1893.]
THE new railway from Upminster to Romford is the most
northerly portion of the line connecting Grays Thurrock with
Romford. In The Essex Naturalist for 1890 (vol. iv., p. 143) I
gave some account of the sections then visible in the most southerly
part of this railway. I there stated that south of Back Lane Chalk
appeared, while between Back Lane and the stream known as the
Mardyke it became covered by the Lower Tertiary formations, the
Thanet Sand and Woolwich Beds, the overlying London Clay being
seen on the northern side of the Mardyke Valley, and thence
constituting the oldest rock visible anywhere, not merely along the
course of the railway, but anywhere southward of the uprise of the
Chalk and Lower Tertiaries in northern Essex.
But a glance at the section given in The Essex Naturalist
(vol. iv., p. 146), showing the arrangement of the beds just mentioned
from West Thurrock to the northern flank of the valley of the
Mardyke, reveals the fact that the surface of the high ground, both
1 For the block of the section and map illustrating this paper, the Editor is indebted to the
courtesy of the Council of the Geological Society.
B