170 
Essex Well-Sections. 
With am. —Railway Station. 
Correction to account in Geological Survey Memoirs, vol. 
iv., p. 445. 
Level of rails about 80 feet above Ordnance Datum. 
From a letter from J. Darby to the Rev. 0. Fisher, 1868. 
[Post-Glacial 
Drift.] 
Coarse gravel [in face of cutting]. 
Sand 
Mixed clay . 
Layer of chalk 
Very hard coarse gravel 
V about 70 ft. 
[Glacial Drift.] Light-coloured clay, becoming 
blue clay with flints . 
Dove-coloured sand (less green 
sand than usual). 
A little red sand, no mottled or 
plastic clay . 
[Eocene 
Tertiaries.] 
“ 
120 ft. 
[“If, as is possible, the bore-hole was dry, the London 
Clay might come up as what is here called ‘ dove-coloured 
sand,’ and the water might be got, as in other wells near, 
from a bed in the London Clay.”—Note from Mr. W. H. 
Dalton.] 
An account of a well at Brentwood came to hand too late 
for insertion, and it will therefore form the starting-point of 
another collection. 
