QUARTZ PEBBLES HAVE COME FROM A DISTANCE. 255 
resemblance to the quartzose pebbles which are accumulated near 
Oxford, and over the other districts which I have been describing. 
So that if they were not transported hither across the depression at 
the head of the valleys of the Evenlode and of the Cherwell, they 
must have passed over some more elevated point of the oolite 
escarpment, and have come from some still more distant part of the 
red sandstone plains that cross the centre of the island; and the 
difficulty of accounting for their origin will thus only be increased by 
refusing to admit the solution I have proposed. 
The quartzose pebbles, which I have been tracing without inter¬ 
ruption from Birmingham to London, had, as I have already men¬ 
tioned, received their roundness before they were embedded in the red 
sandstone formation; their form cannot therefore be referred to friction 
during their short transport by the diluvian waters: indeed instances 
are rare where fragments even of soft rocks, which have undergone no 
further attrition than that of these waters, have received such an 
extreme degree of roundness as is found in the hard quartzose 
pebbles we are considering. Dr. Kidd, in his excellent description 
of the gravel-beds round Oxford, has well and accurately marked the 
differences, between the completely rounded pebbles, and angular 
fragments, of which this gravel is composed; the comparatively soft 
fragments of the neighbouring hills being angular and but slightly 
rolled, and those only being completely rounded which are hard, and 
can be traced up to ancient gravel-beds, forming part of the red sand¬ 
stone strata of Warwickshire # . 
* See the preface to Kidd’s Elements of Mineralogy, and chap. 17 of Kidd’s 
Geological Essays. 
