File:The Quarterly journal of the Geological Society of London (12711740803).jpg

484
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .May 2,
of one mile and a half from the valley of the Coin. At or near its
entrance, the base of the Great Oolite (a), resting on the Fuller's
Earth (b), nearly reaches the bed of the brook. As we ascend towards
Fig
4. — Chedworth Valley.
(Section at the entrance.)
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T~^^
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/ " « 
/I . J ,
o
Level of Brook.
the village, lower beds successively arrive at the' surface ; until after
passing over about 30 feet of Fuller's Earth, we reach the Inferior
Oolite (c). At the village, about 50 feet of this formation compose
Fig. 5. — Chedworth Valley.
(Section through the centre.)
a. Great Oolite.
Level of Brook.
b. Fuller's Earth.
c. Inferior Oolite.
the banks of the brook ; whence continuing our course, we meet with
higher beds, until at the top of the gorge we again reach the Great
Oolite. It is therefore evident that in the centre there exists a
dome-shaped structure of the strata ; the brook forming a datum-
line slightly inclined.
Valleys in lines of dislocation. — A third class of valleys are those
which have originated in, or the directions of which have been locally
marked out by, lines of fault. In this place it would be superfluous
to describe the manner of the formation of such valleys. It will be
sufficient to enumerate several localities where they occur. They
are as follows : — Cranham, west of Painswick Hill ; Painswick Slade,
Cubberley, Winston Wood, Eyeford, Hawling Lodge near Naunton,
and Burford. When no valley occurs along a line of fault, a feature
is generally present, formed of a ridge of the harder beds along the
upcast side.
There is a fourth kind of valley, represented by a few narrow
ravines, especially in the districts occupied by the Great Oolite, the
origin of which cannot be referred to any of the above causes. Some
of these contain brooks which are dry throughout the greater part
of the year, and are too insignificant to be supposed capable of having
excavated any portions of the gorges through which they run. The
formation of these, and indeed all the valleys of the Cotteswold Hills,
must be considered as entirely due to marine agency acting at several
successive periods ; the most ancient dating, perhaps, as far back as