xiv FLORA OF OXFORDSHIRE. 
and thus saved from denudation. In the Evenlode valley they 
exist as a narrow strip on each side, becoming gradually thinner, 
until between Charlbury and Stonesfield they entirely disappear. 
Other strips are seen in the upper portion of the Glyme valley 
about Enstone and Heythrop, and in the Cherwell valley from 
Rousham northwards. Outliers may be observed at Steeple 
Barton, Milcomb, Bloxham, etc. At the base of these Liassic 
clays ‘lies a thin but well-marked series of whitish marly clays, 
with bands of white or cream-coloured earthy limestones’ which 
have been well investigated by Messrs. Beesley and Walford. 
The characteristic fossils include Ammonites serpentinus, A. 
bifrons, A. Normanianus, A. annulatus. 
Lower Oolites. The Northampton sands, as some sandy 
beds which are found upon the Upper Lias beds in North 
Oxfordshire, are called. Epwell Hill, 743 feet high, is capped 
with these sands, which also cover the Rollright ridge and 
stretch southwards to Chipping Norton and east to Duns Tew 
and Steeple Aston. Wigginton, South Newington, Crouch 
Hill and Tadmarton camp are capped with them and many 
outliers are found to the south and south-west of Banbury. 
A narrow strip of country on each side of the Cherwell valley 
from Souldern to Upper Heyford is also covered with them. 
Although the term Northampton sand is given to this forma- 
tion, it is necessary to bear in mind that it includes two 
formations, the lower part belonging to the Inferior Oolite, the 
upper portion to the Great Oolite. Eastwards, in Lincolnshire 
and North Northamptonshire, these beds are separated by 
a thick bed of limestone which has thinned out so as to allow 
these two sands to run together and to become almost indis- 
tinguishable. Ammonites Murchisonie is a typical fossil of the 
Inferior Oolitic sands. 
The high ground capped with these sands yields many in- 
teresting plants, such as Filago minima, F. apiculata, Gna- 
phahum sylvaticum, Galium saxatile, Teesdalia nudicaulis, 
Ornithopus perpusillus, Avena flecuosa, caryophyllea, and pre 
cox, Calluna and Rubus Ideus. 
Great or Bath Oolite. To the south of the district covered 
by the Northampton sands the beds known as the Stonesfield 
slates occur in the form of a laminated sandstone, splitting 
