(See Philosophical
Transactions 1850 page 363; also Huxley Memoirs of Geological Survey 1864;
Phillips Palaeontological Society.)
KELLOWAY ROCK.
The arenaceous limestone which passes under this name is generally 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,
numerous 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 1/2 per cent, are common to the Oxford
clay proper. Of the 52 Cephalopoda, 15 (namely 13 species of ammonite, the
Ancyloceras Calloviense and one Belemnite) are common to the Oxford Clay, giving
a proportion of nearly 30 per cent.
LOWER OOLITE.
CORNBRASH AND FOREST MARBLE.
The upper division of this series, which is more extensive than the preceding or
Middle Oolite, is called in England the Cornbrash, as being a brashy, easily
broken rock, good for corn land.
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