File:The Quarterly journal of the Geological Society of London (13365604743).jpg

1850..
DAVIS ON THE NASH LIMESTONE.
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out towards the west. Its former
course towards Corton may be traced
by the old workings on the south side
of 'Folly Bank.' The shale also thins
out towards the west, but in this di-
rection the order of succession is dis-
turbed by a fault which has let down
an outlier of old red sandstone ex-
tending from 'The Slough' over the
'Deepmoors' to 'Radnor Wood.' Pro-
ceeding, however, from the Sandbanks
in a north-easterly direction across the
valley of the Lug to Stapleton Hill,
a section may be obtained free from
this fault, the line of which appears to
be from above Brook House at Staple-
ton, south-west, to Presteign, Slough,
and Radnor Wood, cutting off the
Upper Ludlow and outliers of old red
sandstone on its north-west, from the
shale and Lower Ludlow on its south-
east side. As from the intervention
of the Knill valley on the south, so
from that of Presteign drained by the
Lug on the north, the precise thick-
ness of shale and Lower Ludlow can-
not be accurately determined. The
shale has been washed away to within
about fifty or sixty feet of the grit by
the denudation of the Presteign valley.
All that can be stated with certainty
is, that leaving the shale at the 'Sand-
banks' on the south side of that val-
ley, at the distance of a little more
than a mile to the north-east, the
Lower Ludlow rock emerges at Sta-
pleton Hill from the gravel, and dip-
ping gently to the N.N.W. passes
under Upper Ludlow beds in Hill
Peak.
An ascending section on each side
of the anticlinal line is thus obtained,
which will be more clearly under-
stood by reference to the annexed
sketch.
Before proceeding to an examina-
tion of the fossil remains of Nash
limestone, the experimentum crucis of
this, as of every other similar geological problem, the evidence from