DAVIS: DISTRIBUTION OF FOSSIL FISHES. 
231 
coal, which is regarded as the dividing line between the Lower and 
Middle Coal measures by the Officers of the Geological Survey, 
there are several important coal seams, but I have not yet suc- 
ceeded in finding any fish remains in connection with either of 
them. 
The Middle coal measures include all the remaining strata of 
the Yorkshire Coal field. Three or four beds of coal in these 
measures have yielded fish remains : the Silkstone coals ; the 
Middleton beds, near Leeds, from which the Agassizian genus 
Megalichthys was derived, the specimen being now in the Leeds 
Museum ; the Joan coal, and the Cannel or Stone coal, worked at 
Bruntcliffe, Ardsley, Tingley, and one or two other places. The 
latter contains a more remarkable series of fossil fish than any other 
stratum in this district ; a detailed description of this coal may be 
found in the proceedings of the Yorkshire Geological and Poly- 
technic Society for 1878. It occupies a basin-shaped hollow 
extending only a few miles, and thinning out in every direction 
from the centre. Other similar areas,* on the same horizon, are 
filled with beds of cannel coal, extending south-westwards from 
Tingley, but in no other instance, so far as I know, do the coals 
possess so rich a fauna as the one named. The cannel coal is div- 
ided into two parts by an intervening bed of black carbonaceous 
shale ; at its base is a bed of ordinary coal, and above it a shale 
filled with ironstone nodules, — both the shale and ironstone contain 
immense numbers of shells of TJnios or Anthracosia, as well as a 
large series of plants. The fossil fish preserved in this coal are 
found in greatest abundance at the junction of the cannel coal 
with the intermediate shale, but they are also scattered somewhat 
indiscriminately throughout the coal. 
Having thus briefly summarized the various strata in the 
West Biding, from which fish remains have been obtained, I 
purpose to consider the several characteristics of the fossils and 
their relations to existing species, so far as they can be made out. 
* See " Geology of the Yorkshire Coal Field," by Prof. Green and other 
Members of the Geological Survey, 1879 
