689 
Claywood or Black Shale Ironstone. This bed is worth the 
notice of local geologists, as it contains many fossils, plants, 
a little crustacean [Cyprls), and Anthracosia. 
The Silkstone Four-foot Coal, which seems to be the same 
as the Wheatley Lime of the Flockton district, lies about 
forty yards above the Silkstone. Traces of this bed can 
generally be found everywhere over the district we are now 
concerned with, but its thickness is most changeable. 
About Sheffield there is often on this horizon a six-inch coal : 
the bed seems to grow thicker northwards, till at Silkstone 
it has been found four feet, but its average in the Barnsley 
district is about two feet six inches. The coal has probably 
been worked about the outcrop, but I have not been able to 
learn anything of its quality. 
The Swilley Coal or Accidental Bed behaves somewhat 
in the same way* as that last described; under one form or 
another, varying from a few inches to two feet, it may be 
pretty generally traced : at one colliery, however, it turned 
out most unexpectedly to be a most valuable seam, 5' 8" 
thick, consisting of three beds, and of most excellent 
quality. 
The New Hards or Cromwell of the Flockton district 
corresponds in position with this bed : it is a good coal, 
averaging about eighteen inches in thickness. 
About eighty yards above the Silkstone is Walker's or 
the Thorncliffe Thin Coal, with ironstone-measures, known 
as the "White Mine, above it. The coal varies between 
Sheffield and Barnsley from 2' 6" to 1' 6" in thickness ; it is 
worked for house-coal at some of the collieries. The iron- 
stone-measures 'have been largely gotten, but are, I believe, 
nowhere worked at present. About Silkstone the coal is 
found sometimes in two beds thick enough to be worth 
working, but is sometimes so split up with dirt as to be 
unworkable ; it goes thereabouts by the name of the Thorn- 
