Page:The South Staffordshire Coalfield - Joseph Beete Jukes - 1859.djvu/92

74

(See Vertical Sections, sheet 26, No. 42.)

Hammerwich Colliery, below the dam of the Reservoir.

(See Vertical Sections, sheet 16, No. 2.)

33. Measures between the Bottom coal and the Gubbin and Balls ironstone.—The Bottom coal usually rests on a bed of fire-clay some feet in thickness. In many instances, however, this is wanting, and the coal rests on hard sandstone, the change from one material to the other being sometimes very abrupt. Wherever the Gubbin and Balls ironstone exists, it is found at a distance below the Bottom coal varying from 5 feet to 30 feet, the most usual distance being 15