FRUITLESS TRIALS FOR COAL. 493 
pounded felspar, kaolin, or other ingredients according to circumstances- 
are added."* 
Clays belonging to the Forest Marble have in some places been worked 
for brick-making, as at Siddington, near CJrencester, Badminton, Black- 
thorn near Bicester, &c. 
The Great Oolite Clay is occasionally employed for brick-making, as 
noted by Prof. Judd, at Bedford Purlieus, and New England near Peter- 
borough. 
Lignite and Bituminous Shale. 
No beds of lignite and bituminous shale that have proved to be- 
of economic value, are known to occur in the Lower Oolites ot 
our district. Their presence has in some instances led to futile 
searches for coal. 
The Upper Estuarine Beds at Aunby, Lincolnshire, contain bituminous 
layers with lignite and impure coal, as noted by Prof. Morris. In the 
Great Oolite Clay of Silk Willoughby, a thin band of lignite was proved 
in a well-boring. The Forest Marble frequently contains lignite. 
During the construction of the railway at Trowbridge specimens were 
used as fuel by the workmen. Occasionally the lignite approaches jet in. 
character. 
About the year 1835 an attempt to find coal was made by boring at 
Kingsthorpe, Northampton ; and in reference to it Dr. Bnckland is 
stated to have said, " You may fry me over the first shovel- full of coal 
that comes out of this pit.''f The boring was carried through the Oolites 
and Lias 860 feet, and to a total depth of 967 feet. 
Another useless trial for coal, is noted as having taken place in the 
Forest Marble near Cirencester,^ probably on account of the lignite so 
often present in that formation ; while a boring was commenced about 
15 years ago in the same formation, at Luckington, east of Badminton,, 
and this was not carried to a sufficient depth to prove the Palaeozoic floor. 
At Stratton Audley a boring in search of coal, was commenced in the 
Cornbrash, and carried to a depth of 243 feet, perhaps into the Middle 
Lias. 
In the Radstock district of Somerset, true Coal-measures are worked 
beneath the Inferior Oolite and Lias : in no other part of the country has 
coal yet been worked under a similar sequence of strata. At Dover, 
Coal-measures have been reached beneath Bathonian beds (p. 362) ; and 
they were proved beneath the Jurassic rocks at Burford (p. 304.). 
Iron Ores. 
Iron-ore is extensively worked in the Inferior Oolite Series of 
Northamptonshire. It consists for the most part of Brown 
Haematite or Limonite, the hydrated peroxide of iron. 
Prof. Judd, to whom we are most largely indebted for our 
knowledge of the strata, remarks that there is evidence that, at 
least as early as the period of the Roman occupation, the beds of 
brown ironstone were known and extensively worked. Thus in 
a wood near Oundle, heaps of broken ore, and large quantities of 
slag occur, associated with which have been found Roman coins 
and pottery. Again there is historical evidence that in mediaeval 
times, the district of Rockiugham Forest vied with that of the 
Weald of Sussex and Kent, as a great iron-producing district, 
* Judd, Geol. Rutland, pp. 189, 201. 
t J. L. Baker, Essay 011 the Farming of Northamptonshire, 1852, p. 22 ; Sharp r 
Quart. Journ. Geol. Soc., vol. xxvi. p. 364 ; Letters of J. B. Jukes, 1871, p. 4G8. 
I J. Buckman, Geologist, vol. i. p. 186. 
Greeu, Geol. Banbury, p. 23. 
