230 
DAVIS : DISTRIBUTION" OF FOSSIL FISHES. 
where found are nearly always associated with molluscaof a marine 
origin, such as Goniatites, Nautilus, Avicula-pecten, and Orthoceras. 
About 700 feet above the base of the coal measures is the Elland 
Flagstone, known south of Hudders field as the Grenoside Rock, 
and immediately above these flagstones there is a bed of coal, two 
and a half feet thick, the Better Bed Coal ; it is peculiarly free 
from sulphur and in consequence is valuable for iron smelting : the 
excellence of the Low Moor Iron has been attributed in a great 
measure to the use of this coal. It possesses a further character- 
istic of interest to students of fossil botany, viz, that in some 
paits of the seam the coal is made up of the macrospores of fossil 
plants, so well preserved that the microscope reveals their structure 
and botanical affinities with much perfection. The most important 
feature in connection with this coal, for our purposes, is constituted 
by the presence of a thin stratum of shale immediately above it, 
which is to a very great extent made up of fish remains. So com- 
pletely is this the case that I have ventured in the proceedings of 
the Geological Society of London to describe it as a Bone-bed.* 
It extends for several square miles, overlying the coal, and is 
nowhere more than half an inch, generally not more than one 
quarter of an inch in thickness. From this thin stratum have been 
obtained nearly forty spt-cies of fossil fish and labyrinthodonts. The 
remains are frequently broken and appear to have been a good 
deal rolled about before they became finally embedded. They 
consist of about equal proportions of marine fishes and of those 
which live in fresh water at the present time. 
The next important coal is the Black-bed seam. It is exten- 
sively wrought near Bradford and Halifax : in the shale above the 
coal there is an extensive deposit of Clay-Ironstone, the two being 
worked together. Many important fossils have been found in the 
shale near its junction with the coal, and especially a large laby- 
rinthodont, Pholiderpeton scutigerum, named and described by Prof. 
Huxley. From the Black-bed coal to the Silkstone or Blocking 
Quar. Jour. Geol. Society, vol. xxxii, p. 332, 1876. 
