ASHLEY : NOTES OX ADWALTOX AXD HALIFAX COAL. 
259 
Bed shown is about 36 miles, while the longest section running 
through the cannel coal is only about eight miles. 
While the roof of the cannel coal and the Hard Coal are alike 
inasmuch as over the area traced they both contain marine fossils, 
the floor of the Hard Coal is always practically the same, whereas 
the floor of the cannel coal varies exceedingly, being sometimes 
shale and sometimes bright coal. Furthermore, as already indi- 
cated, the marine organisms are found actually embedded in the 
cannel, which is not the case in the Hard Bed. 
The cannel coal occurs in the form of a lenticular patch, 
having its greatest thickness in the neighbourhood of Batley, 
and thinning out north, south, and east. Unfortunately, it is 
impossible to say what takes place to the west, as the seam 
crops out about two miles west of Batley. 
The Hard Bed, on the contrary, is not lenticular in form, 
and is much more constant in thickness. 
The cannel coal contains a high percentage of mineral 
matter, and also numerous remains of marine organisms, all of 
which are quite consistent with the view that it is a deposit 
of drifted material laid down in shallow water, and the fact that 
it never has a definite under-clay or other bed which would have 
been likely to serve as a floor on which the vegetation of which 
it is composed could have grown, there seems to be little doubt 
that it is actually a drift coal. 
The Hard Bed, on the other hand, contains a percentage of 
mineral matter so low as to be quite inconsistent with the drift- 
wood theory, since the currents which carried the vegetable 
matter would in all probability have carried also sand, or at all 
events fine silt. This silt, on being deposited, would of course 
largely increase the percentage of mineral matter. 
The coal is so constant in thickness over such a wide area 
that it seems impossible to attribute it to deposition in shallow 
water. 
The ganister upon which the Hard Coal rests consists, as 
already stated, of nearly pure silica, there being an almost entire 
absence of potash and iron. It is penetrated in all directions 
