332 J. W. DAYIS ON A BONE-BED IN THE LOWER COAL-MEASURES. 



36. On a Bone-bed in the Lower Coal-measures, with an Enume- 

 ration of the Fish-remains of which it is principally composed. 

 By James W. Davis, Esq., E.G.S., F.L.S. (Read June 7, 1876.) 



Near Bradford and Clifton, in Yorkshire, a peculiar stratum of shale, 

 which contains so great a number of remains of fossil fishes that I 

 venture to call it a bone-bed, occurs immediately above the Better- 

 bed coal, and is known to extend over a surface four or five miles 

 in length by about two in average breadth. 



The Better-bed coal is a member of the Lower Coal-measures, or 

 Gannister series. It occurs about 700 feet above the Rough rock, 

 the uppermost bed of the Millstone grits, and is separated from the 

 Black-bed coal by overlying strata of an average thickness of 120 

 feet. It is extensively worked by the Low-moor Iron Company, 

 and used by them in smelting the clay-ironstone of the district. It 

 is peculiarly valuable for this purpose on account of its freedom from 

 sulphur, the excellence of the iron manufactured by this firm being 

 in a great measure ascribed to the use of the Better-bed coal. 



The following section (p. 333) will explain the position of the 

 bone-bed. The section extends from the thick series of sandstones 

 known as the Elland Flag rock, below the Better-bed coal, to the 

 Black-bed coal above. 



The beds vary very much in thickness within even a small 

 area, the sandstones and shales often thinning out from a thickness 

 of from twenty to forty feet in less than a mile, and altogether 

 disappearing. The most persistent beds are the coals and the fire- 

 clays, or seat-earths on which they rest. The section may be taken 

 as a fair average in this locality. 



The bone-bed rests immediately on the surface of the coal, and 

 varies from a quarter to five eighths of an inch in thickness. Above 

 is a thick bed of blue argillaceous shale containing layers of iron- 

 stone nodules, the only organic remains found in it being those of 

 plants. The bone-bed is composed in a great measure of commi- 

 nuted bones, principally of fishes, though remains of Labyrinthodonts 

 are sometimes found ; mixed with these are minute fragments of 

 coal, often in thin layers of small extent. The whole presents 

 the appearance of a brownish-black, argillaceous shale, and is easily 

 distinguished from the light-bluish shale above. It is continuous 

 over a large area, being invariably found (where the coal has been 

 worked) from the north-west of Wyke, near Bradford, to Clifton. 

 Nearly all my specimens are from the latter district. 



I would briefly draw attention to the section, in order to point 

 to the probable circumstances attending the aggregation and depo- 

 sition of the strata composing it. Beginning with the Elland Flag- 

 rock, we find it composed of a great thickness of sandstones, with 

 intercalations of shale, which were probably of littoral origin, or 

 ma)' have been the estuary of a large river. A gradual elevation of 



