File:The Quarterly journal of the Geological Society of London (13365630713).jpg

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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .Juiie 5,
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§ I

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§.2 3
9 ai
appears to have been greater towards the
N.E., and less towards the S.W. ; for whilst
it is probable that at Deptford the displace-
ment does not exceed 90 feet, at Greenwich
it is about 120 feet (see Section, fig. 6), and
in the Greenwich Marshes 1 60 feet ; the chalk
being 1 24 feet from the surface at Greenwich
Hospital ^, and 55 feet of London clay having
been pierced in the Marshes.
South of New Cross, on the contrary, the
dislocation (which at Deptford produced six
faults) is reduced to a few undulations and
one fault. (See Section, fig. 6.)
About a mile and a half south-east of this
line of disturbance, and parallel to it, there
ranges another hue of fault, a section of which
was formerly to be seen near the lane behind
Morden College, and near the Tiger's Head
at Lee. The effect of this dislocation is that
the London clay occupies all the low ground
drained by the Lee Stream, a position not due
to it by the dip of the strata, which does not
exceed 2°. There is evidence of the exist-
ence of faults near Elthara, Chiselhurst, and
Bromley.
In the hollow of Tranquilvale is a recon-
struction of the strata which crop out in the
sides of the valley. This was well exposed
in the cutting east of the Blackheath Station.
The section (fig. 7) exhibits the contor-
tions of part of this reconstruction, the un-
disturbed bed at the base being the ash-
coloured sand (No. 2) with ferruginous strings
and concretions. The fragments of shell are
derived from No. 4 ; the coloured clay and
greensand from No. 3.
These contortions may be owing to glacial
action ; and there is evidence of action of the
same kind in the centre of Blackheath. It
is not impossible that the few feet of loam,
&c. which there lie on the pebble-bed may be
a reconstruction (if not the commencement)
of the London clay.
All the low ground about the Lee Stream

• The following series of beds were penetrated by
  

the well at Greenwich Hospital : alluvium, 10 feet ;
gravel (drift or " pebble-bed " ?), 35 feet ; black sand,
blue clay, and shelly rock (equivalent to No. 4), 9 feet ;
red clay, white sand, and green sand and pebbles