298 LIAS OF ENGLAND AND WALES I 
desirable ; as lime is said to diminish the contraction of the raw 
brick in drying, and it acts as a flux in burning, causing the 
grains of silica to fuse, and thus binding the particles of the 
brick together.* This calcareous matter must be in a finely 
divided state. 
Some of the clays are too calcareous, more especially those that 
alternate with the limestones in the basement portions of the 
Lower Lias. Thus at the Rugby quarries, the clays and shales 
contain about 30 per cent, of carbonate of lime, and are therefore 
unsuitable for the manufacture of bricks ; but at Hill Moreton not 
far off the clays at a higher horizon, furnish a superior brick. In 
other cases shells and small calcareous nodules or "race," the pre- 
sence of which would be apt to " blow " the bricks, render the 
clays unsuitable. Iron-pyrites again is objectionable, and must 
be removed from the clays. 
In many localities the Lower Lias clays, above the mass of the 
stone-beds, are employed for brick-making and other purposes. 
Thus at Lyme Regis, bricks, tiles and pipes are manufactured, 
and this is the case at intervals throughout the country to 
Lincolnshire. Some of the best bricks are made at Hill Moreton 
near Rugby, Their red colour is said to become brighter after 
use and exposure in buildings. They keep out damp, and are 
often recommended in specifications for facing. 
At Shepton Mallet remains of a Roman Potter's kiln were 
discovered in 1864,t and the material that had been used was 
probably the Lower Lias clay, which is used for brick-making in 
the neighbourhood. 
The Lower Lias clay is used in potteries at Cranham near 
Painswick (see p. 143), and at Loseby, E.N.E. of Leicester (see 
p. 170), and the Upper Lias clay was used at Fawler. Only the 
coarser kinds of earthenware are manufactured. 
. Most of the Lower Lias clays are stiff and calcareo-argillaceous 
or shaly ; there are seldom any loamy beds, such as are naturally 
adapted for brick-making. Milder or loamy earths are to be 
found in the lower part of the Middle Lias, and such beds are 
worked south of Alliugton near Bridport, near Ilminster and 
Glastonbury, at Stroud, Banbury and other places. 
In the Upper Lias the clays are usually stiff, but in Dorsetshire 
and Somersetshire they are loamy in character. These milder 
beds are worked for brick-making near Bridport and at Yeovil. 
The Upper Lias clays are most extensively worked for making 
bricks, tiles, and drain-pipes, from the neighbourhood of Banbury, 
through Northamptonshire to Lincolnshire. 
Near Northampton, " Cimolia " of a dark lead colour was for- 
merly used for making tobacco-pipes. J At the present brickyards 
near Kingsthorpe, red bricks and tiles are manufactured, includ- 
* Notes on Building Construction, Part III.'(Rivmgtons), p. 8C>. 
f Eev. H. M. Scarth, Proc. Somerset Arch, and Nat. Hist. Soc., vol. xiii. p. 1. 
j J. Woodward, Nat. Hist. Foss. England, Part I., 1729, p. 4. Cimolia is a term 
that has been applied to fuller's earth. 
