XXVili FLORA OF OXFORDSHIRE. 
plateau, on which, at the New Inn, it turns south-easterly by 
the road to Stanton St. John, to Forest Hill and follows the 
London road to Oxford. This boundary is artificial, and one 
which does not take in the whole of the Cherwell drainage, ex~ 
cluding as it does about 200 acres on the south of the road. As, 
however, this portion is the northern escarpment of the Shotover 
range, which geologically belongs to the Thame district, this 
boundary has been selected instead of a purely natural one in 
order to avoid confusion. From Oxford the boundary follows 
the Banbury road as far as Stratfield farm, pursues a north- 
westerly direction to Round Castle, and thence runs nearly due 
north, on the 1.20 line to Sturdy’s Castle, by Tackley Heath 
and Hopcroft’s Holt to Dunstew—the Banbury turnpike road 
fairly marking the boundary from Sturdy’s Castle northwards. 
The main stream of the Cherwell between Somerton and the 
Heyfords, passes through interesting ground, rich in marsh 
plants, and its waters are frequently ornamented in its southern 
course by masses of white and yellow lilies. Passing Rousham, 
at Northbrook bridge, the Cherwell finally leaves the Liassic 
strata, and enters on the Oolitic. Flowing by Tackley heath, 
and Kirtlington park, past Epslow quarries, and the road- 
side festooned with Clematis, it enters upon the Oxford Clay, 
which forms henceforward its bed, as it curves by Hampton, 
through its flat alluvial meadows by Kidlington and Water 
Eaton. Near Islip it receives the Ray, a many-headed 
stream; one of its largest feeders, rising in Buckinghamshire 
near Edgcott, enters Oxfordshire near Piddington, and drains 
—if this term can be appropriately applied—the flat ugly marsh 
of Otmoor and the bare country round. Another feeder comes 
from Poundon, by Bicester, and joins the Edgcott brook at Merton, 
the Bicester brook, receiving near Wendlebury a stream rising 
on the Oolite near Ardley, continuing in a tongue of that 
stratum, nearly through the belt of Cornbrash to Chesterton, 
whence its passage southwards is through the Oxford Clay. 
Several other brooks serve as feeders but they possess little 
interest, so we rejoin the Cherwell at Water Eaton, which cuts 
its way through pretty scenery to Marston, its banks adorned 
with fine old willows and handsome thorns, while its waters here 
and there show Hydrocharis and Typha angustifolia. Weaving 
