Mr. J. Lycett on the so-called Sands of the Inferior Oolite. 143 
ascertained, that at present it would be injudicious to indulge 
in absolute conclusions respecting it. This sandy deposit must 
be seen to be fully appreciated: presenting much variability in 
its thickness throughout its long course in the Cotteswolds, it 
is everywhere readily recognized, and even the approximate 
position of any small exposures of it may be predicated with 
tolerable exactness. Unfortunately, nearly the whole of the 
Cotteswold sections are of a small and imperfect character, con- 
sisting chiefly of cuttings of rock upon deep lane-sides, or upon 
the banks of water-courses ; and although these in the aggregate 
exhibit the entire physical features of the deposit, they do not 
enable us to ascertain the thickness of the whole, in particular 
localities, with any near approach to accuracy. We can there- 
fore only estimate the thickness by tracing upwards the beds 
upon hill-sides, and occasionally by examining the rock brought 
up during the process of well-sinking. From information ob- 
tained in this manner, it would appear that the thickness of the 
sands varies in the middle Cotteswolds from 35 to 80 feet ; and 
Mr. Hull has shown that over the northern and southern Cottes- 
wolds they present even a greater amount of variability in thick- 
ness. My own observations lead to the conclusion, that, like 
the mass of the Inferior Oolite generally, the thickness is greater 
upon the outer western escarpment of the Cotteswolds than in 
the interior valleys, where they are far remote from the outer 
range. In tracing upwards the beds from the Lias there occurs 
the following general order of succession :— 
soragtaer lias clay, grey or blue, soft, and clearly distinguished 
rom 
B. Brown or chocolate-coloured, marly, micaceous sandstone, 
with frequent red ferruginous stains between the lamination; 
occasionally the stone is more argillaceous, and buries the 
hammer when struck; in other instances, from the presence 
of portions of shells, it is more hard, but is peculiarly irre- 
gular and uncertain both in hardness and colour, varying 
from a blackish-grey to a bright foxy or reddish hue, every- 
where glittering with micaceous particles. At about 4 feet 
from the base are usually one or two thin bands charged with 
fossils, the greater number of which are very imperfectly pre- 
served: this may be designated as the lower shelly zone, and 
may be studied in small Jane-side sections at Nailsworth and 
at Brimscombe. In the Yorkshire exposition of the deposit, 
I shall subsequently show that a shelly zone occurs in a similar 
position. Passing upwards from 10 to 20 feet, there occurs 
a general diminution of compactness in the rock, and of its 
marly structure ; there gradually sets in 
