QUARTZQSE PEBBLES IN MIDLAND COUNTIES. 
249 
VALLEYS OF DENUDATION, AND BEDS OF DILUVIAL 
GRAVEL, IN WARWICKSHIRE, OXON, AND MID¬ 
DLESEX. 
The details of the second case I proposed to give in this ap¬ 
pendix are those which relate to the excavation of valleys, and the 
dispersion of beds of gravel, in the county of Warwick, and along the 
course of the Cherwell, Evenlode, and Thames, from Warwickshire 
to Oxford and London. 
The new red sand-stone formation, in the central parts of Eng¬ 
land, contains an enormous deposit of pebbles of compact granular 
quartz, forming large beds, which may be seen near Bridgnorth, Lich¬ 
field, and Birmingham. They here constitute a regular stratum, 
subordinate to the red sand-stone, having been reduced to the state of 
pebbles by the action of violent waters, at or before the time of the 
deposition of this formation. From this lodgment, in one of the 
deep and regular strata of the country, enormous quantities of the 
pebbles in question have been swept away by the diluvial waters, and 
dispersed superficially over the adjacent districts and midland coun¬ 
ties, without any reference to the nature of the rocks that lie beneath, 
and mixed with fragments of other rocks, both older and younger 
than the red sand-stone*. 
* For a detailed account of the geological history of these pebbles, and of the source 
from which they were originally derived, I must refer to my paper on the quartz rock of 
