File:The Quarterly journal of the Geological Society of London (13071081065).jpg

478 PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
Fig. 2. — Section of Lias and Carhoniferovs Limestone, at Whatley.
J Drifted deposit, partly composed of a ferruginous clay, ft. in.
■ 1_ enclosing blocks of Inferior Oolite 4
7 r Grey clay with Argiope, Suessia, Spirifera, Pentacri-
B. ^ 1 nites, &c 10
a. Grrey laminated micaceous marl, without organisms . . 12
C. Carboniferous Limestone, exposed 3
The Carboniferous Limestone, which, though almost vertical, is
seen to have been worn down to a very horizontal surface, is only
open in this section for a few yards in length.
The uppermost deposit (c) is much hidden by the vegetable growth
of the embankment, and must be as late as the Oolite, since it con-
tains blocks of that age, having many imperfect casts of Echinoder-
mata, with Lima gibhosa and Litliodomi. This is evidently a drifted
deposit, and has mixed up with it many blocks of sulphate of barytes.
The Oolite in this immediate neighbourhood, whenever it comes in
contact with the Carboniferous Limestone, puts on very peculiar mine-
ralogical conditions, its under sui^face being at times an iron-ore,
whilst at others it is very porous and full of canities, the matrix
being composed of sulphate of barytes. On the opposite side of the
roadway an oolitic rock is visible, which probably belongs to the
Fuller's earth, as the clays of this formation come in immediately
above it.
B. The Lias, 2 feet in thickness, which is intermediate between
the Carboniferous Limestone and the Inferior Oolite, may be divided
into two parts : — the first (a) is composed of a bluish or grey la-
minated micaceous marl ; but after careful search I have hitherto
been unable to detect any fossils in it.
6. The bed which follows is seen to rest immediately on the Car-
boniferous Limestone. In its upper part the fossils are rare, but, as
it reaches the limestone, they become more abundant, and the base-
ment is seen to be almost entirely composed of Brachiopoda , Echini,
Pentacrinites, (fee, which are held together by a somewhat friable
calcareous matrix. Occasionally, on the Carboniferous Limestone, its
base is converted into a thin indurated limestone, which is difficult
to separate from the older rock.
That this remarkable representative of the Fontaine-etoupe-Four
Lias is very local, there cannot be a doubt ; for immediately below