of the Great Oolite of Minchinhampton. 117 
clay, we find an alternating series of limestones and clays or 
marls, extremely variable both in thickness and extent. Certain 
of these bands, and more especially one of a compact cream- 
coloured limestone, are eminently shelly, but will seldom allow 
of the shells being separated entire. These gradually pass down- 
wards into the middle subdivision, where the rock is more bar- 
ren of organic remains, and sandy. 
The lower subdivision assumes a very different aspect : we 
here find 35 or 40 feet of shelly beds, separating into large 
masses, and well suited for the mason. From the third or lower 
subdivision it is that nearly the whole of our fossils are derived, 
the stone usually admitting their being cleaved with a knife. 
The uppermost portion of this series, the planking*, which is 
from 8 to 10 feet thick, contains the most numerous suite of zoo- 
phagous Trachelipods, several of which are not found beneath it. 
To this succeeds a few feet of incoherent sandy rock, the upper 
part of which is nearly destitute of shells, or only occupied by a few 
species of small bivalves. The shells gradually increase in number 
downwards, and repose on several beds of hard shelly rock, 
locally called Weatherstone. Here more especially abound the 
valves of small oysters, which at length constitute no inconsider- 
able portion of the mass, and whose peculiar structure imparts 
such great hardness to the deposit, that the lower few inches 
strike fire with the tools of the workmen. 
These shelly beds or weatherstones have a high character for 
durability ; they have a coarse aspect ; when once dried by ex- 
posure to the sun they do not readily absorb water, and conse- 
quently resist the action of frost ; a careful selection is however 
necessary to ensure this desideratum. The south transept of 
Minchinhampton church, five centuries old, is built of this stone, 
and notwithstanding its very exposed situation, displays all the 
sharpness and distinctness in its angles and carving which we 
should expect in a modern edifice. 
The Fuller^s earth which underlies these deposits is but par- 
tially and imperfectly exposed within the district ; it consists of 
a series of brown and blue marls and clays traversed by three or 
four bands of a hard argillaceous rock locally called clay rag. 
Some portions of the clays, and more especially the rag-stones, 
are made up of the valves of small oysters, chiefly Ostrea acumu 
nata ; the organic remains however are far from numerous 
when counted by number of species ; they are nearly all bivalves, 
and I have not observed any which are not likewise found in the 
weatherstones above. The Fuller^s earth constitutes the most 
fertile soil in this part of the county ; when properly drained it 
A local term indicating a thin-bedded stone. 
