SPENCER : ON THE GEOLOGY OF CALDEEDALE. 
371 
In the neighbourhood of Denholme these shales partly give place to a 
thick-bedded sandstone which is very rich in fossil plants (casts). 
Then we have more shales followed by the Soft Bed Coal (16 in.) 
with a roof which yields a few fish remains, but in which fossil plants 
are rare. Then follows about twelve feet of grey shales, upon which 
are three beds of Anthracosia, which are separated from one another 
by two thin beds of black shale, which contain quantities of Spirorbis 
carbonarius. In the Low Moor Coal series there is a bed several feet 
in thickness almost entirely composed of these small coiled shells. 
Twenty-five yards above the Soft Bed Coal the Hard Bed Coal 
is reached ; halfway between them is the Middle Band Coal, about 
ten inches in thickness, w 7 hich is worked about Halifax in connection 
with the fireclay upon which it rests. Below the latter is a fine- 
grained sandstone from three to five feet in thickness. 
The Halifax Hard Bed Coal is overlaid by a bed of marine 
shells consisting mainly of Aviculopectens. Immediately above this 
bed come six to twelve feet of shale, containing a large number of 
calcareous balls, locally known as " baum pots," which contain 
marine shells, Goniatites Listeri being especially common. 
In the Hard Bed Coal itself there are other balls, generally coated 
with pyrites, but containing fossil plants showing the vegetable struc- 
ture as well as the form. No less than nine species of Lepidodendron, 
six species of Sigillaria, ten of ferns, as well as Calamites, Astro- 
myelons, and many other coal plants are thus preserved, and even 
the parasitic fungi which preyed upon them are found in a beautiful 
state of preservation. When cut into thin slices the tissues of the 
plants can be examined under the microscope almost as easily as 
those of living plants. 
These Goniatite Beds are followed by thirty yards or more of 
" hard bands/' a ragstone, composed of thin layers of stony shale, 
containing a large percentage of silica, forming a thin-bedded but 
very hard rock. This is followed by three to six feet of seat earth, 
upon which reposes the 36 Yards Band Coal, six to eight inches in 
thickness. Upon this coal rests about twelve yards of shale or "bind," 
followed by the 48 Yards Band Coal, six to ten inches in thickness ; 
in some places there are two beds of coal with a foot of seat-earth 
