Abstract

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