524 
Mr. Buckland on the 
great, that the head springs of the Evenlode, taking their rise from 
the lias strata in the vale of Moreton beyond the termination of 
the oolite escarpment, flow south-eastward toward Oxford (through 
the same gap by which the diluvian current drifted in the siliceous 
pebbles,) instead of falling by the course of the Stour to Stratford 
on Avon, by what, without this lip, would have been the natural 
drainage of the vale of Moreton ; and it is of importance to observe, 
that the Evenlode and Cherwell are the only rivers of all those 
which flow down the back of the inclined planes of the oolite 
strata into the Thames, which have not their head-springs within 
this escarpment of the great oolite. The sources of the Cherwell 
and a few of its earliest tributary streams being similarly circum- 
stanced to those of the Evenlode, are thrown out in consequence 
of similar denudations cut through the oolite strata into the clay 
beds of the subjacent lias, even as far down as the town of Banbury 
and villages adjacent to it on the south. 
The Warwickshire quartzose pebbles occur in the surface gravel 
waters ; and indeed has rendered the form, inclination, hardness, and relative position of 
the masses on which they had to operate, essential elements of any accurate calculations 
of the quantity of effect they have produced ; and though traces of diluvian action are 
most unequivocally visible in the features of every valley of the earth, we must not 
attribute the origin of them all exclusively to that action. In such cases as we have been 
describing, the simple force of retiring water on the surface of gently inclined and regular 
strata of chalk and oolite, is sufficient for the effect produced ; but in other cases, more 
especially in mountain districts, where the greatest disturbances appear generally to have 
taken place, the original form in which the strata were deposited, and the subsequent 
concretions to which they have been submitted, the fractures, elevations, and subsidences 
which have effected them, and their partial destruction at early periods by the violent 
actions of water, (of which the evidence is contained in the various beds of conglomerate 
that alternate with the secondary strata and transition rocks ;) all these and perhaps 
many other causes may have contributed to produce vallies of various age and form upon 
the surface of the earth, before it was submitted to that last universal and recent deluge, 
w hich has finally modified them all. 
