FOSSILS OF THE OXi^ORD CLAY 
341 
Kelloway Rock. —The arenaceous lime¬ 
stone which passes under this name is gen¬ 
erally grouped as a member of the Oxford 
clay, in which it forms, in the south-west of 
England, lenticular masses, 8 or 10 feet thick, 
containing at Kelloway, in Wiltshire, numer¬ 
ous casts of ammonites and other shells. 
But in Yorkshire this calcareo-arenaceous 
formation thickens to about 30 feet, and 
constitutes the lower part of the Middle 
Oolite, extending inland from Scarborough 
in a southerly direction. . The number of 
mollusca which it contains is, according to 
Mr. Etheridge, 143, of which only 34, or 
23^ per cent., are common to the Oxford 
clay proper. Of the 52 Cephalopoda, 15 
(namely 13 species of ammonite, the An- 
cyloceras Calloviense and one Belemnite) 
are common to the Oxford Clay, giving a 
proportion of nearly 30 per cent. 
LOWER OOLITE. 
Fig. 328. 
Cornbrash and Forest Marble. —The upper 
division of this series, which is more exten¬ 
sive than the preceding or Middle Oolite, is 
called in England the Cornbrash, as being a 
brashy, easily broken rock, good for corn 
land. It consists of clays and calcareous 
sandstones, which pass downward into the 
Forest Marble, an argillaceous limestone, 
abounding in marine fossils. In some 
places, as at Bradford, this limestone is re¬ 
placed by a mass of clay. The sandstones 
of the Forest Marble of Wiltshire are often 
ripple-marked and filled with fragments of 
broken shells and pieces of drift-wood, having evidently 
been formed on a coast. Rippled slabs of fissile oolite are 
used for roofing, and have been traced over a broad band 
of country from Bradford in Wilts, to Tetbury in Glouces¬ 
tershire. These calcareous tile-stones are separated from 
each other by thin seams of clay, which have been deposited 
upon them, and have taken their form, preserving the undu¬ 
lating ridges and furrows of the sand in such complete in¬ 
tegrity, that the impressions of small footsteps, apparently of 
crustaceans, which walked over the soft wet sands, are still 
visible. In the same stone the claws of crabs, fragments 
Belemnites Puzosianus, 
d’Orb. B, Oweniiy 
Pierce. j 
Oxford Clay. Christian 
Malford. 
a. Section of the shell 
projecting from the 
phragmacone. 6-c. 
External covering 
to the ink-bag and 
phragmacone. c, d. 
Osselet, or that por¬ 
tion commonly call¬ 
ed the belemnite. e. 
Conical chambered 
body called the 
phragmacone. /. 
Position of ink-bag 
beneath the shelly 
covering. 
