GREAT OOLITE: CHIPPING NORTON. 325 
that formation of important beds of limestone (Chipping Norton 
Limestone), that mark a higher horizon than the Clypeus Grit of 
the Cotteswolds. This Chipping Norton Limestone is far from 
fossiliferous, it is variable in character, and becomes very sandy 
in places, and we cannot always, in the small quarry -sections, 
determine with certainty the precise age of some of the oolites. 
Detailed mapping on the 6-inch scale can alone settle some of 
the uncertainties. 
The basement-beds of the Great Oolite Series consist, in many 
places, of flaggy and shelly oolite, with Nerincea, overlying dark 
grey or black clay with " race " and marl (a few feet thick). 
Lumps (apparently rolled) of limestone, form at the base a 
remanie bed, not unlike that which is here and there seen on top 
of the Great Oolite, at its junction with the Forest Marble. 
The name " Rift Bed " has been locally applied by Mr. E. A. 
Walford, to this bottom layer, which rests irregularly on different 
members of the Inferior Oolite. Much tufaceous rubble some- 
times accompanies it, and the clay fills rifts or hollows of the 
underlying strata. In part, this Rift Bed may be due to dissolu- 
tion of the underlying beds, as the infillings sometimes occur in 
irregular pipes, as well as in joints of the stone-beds. 
Mr. Tomes and Mr. Walford have noted the occurrence of the 
Coral, Cyathophora Bourgucti, in the " rifted " bed on top of the 
Inferior Oolite in the Hook Norton railway-cutting.* This 
species has also been found by them in the Great Oolite (above 
the Stonesfield Slate-beds) in the Ashford Bridge railway-cutting, 
near Stonesfield. (See p. 318.) 
At Chipping Norton, remains of Cetiosaurus have been obtained 
from the local basement-bed of the Great Oolite Series ; and it 
was probably in the flaggy and shelly oolite in " Smith's quarry," 
at Sarsden, that a humerus of Cetiosaurus was obtained by Earl 
Ducie, for it was " imbedded in the rock " ; the beds in that 
quarry have also yielded remains of the Ornithosaurian, Rhampho- 
cephalus depressirostris.^ 
At Enslow Bridge, the remains of Cetiosaurus come from the 
higher beds of the Great Oolite, while Ornithosaurians elsewhere 
occur in the Stonesfield Slate. Palseontological evidence is not a 
certain guide for fixing horizons in the Great Oolite. At the 
same time, I cannot help thinking, on stratigraphical grounds, 
that from the area of Stonesfield, northwards to Chipping Norton, 
and Hook Norton, the basement-beds of the Great Oolite itself, 
are not everywhere on the same horizon, and that some layers are 
impersistent and overlapped by higher stages. 
The section at the old lime-kiln, north of Castle Barn, and 
south-east of Sarsden, was as follows! : 
* Quart. Journ. Geol. Soc., vol. xxxix. pp. 172, 230. 
f Phillips, Geol. Oxford, p. 274 ; Huxley, Quart. Journ. Geol. Soc., vol. xiv. p. 
658. 
J See p. 153 of this Memoir; also Hull, Geol. Woodstock, p. 16. 
