496 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



Halesowen Sandstone Group; (2) The Red Coal Measures Clays; 

 (3) The Coal Measures. The first and second are each about 300 

 feet thick ; the Coal Measures have a minimum thickness at the 

 south of about 400 feet and increase northwardly to possibly 1,300. 



The Halesowen Sandstones and the Red Clays were thought for 

 a long time to be Permian, but careful study by Ramsay, Hull and 

 Jukes fixed their place finally in the Coal Measures. The Hale- 

 sowen sandstones are olive-green, brownish to yellow sandstones 

 with two thin coals. They rest on a mass of red, green and mottled 

 clays containing a thin coal, occasionally 9 inches thick. The pre- 

 dominating color is red. 



Six persistently important seams of coal are present in the Coal 

 Measures along with a much larger number of thin or dirty seams, 

 which are without value. Among the latter is the Herring Coal in 

 upper part of the section; it is a local deposit, almost worthless as 

 coal, but is of interest because it contains great numbers of fish 

 spines, whence the name given by miners. The remarkable feature 

 in this field is the tendency of coal seams to divide, shown most 

 strikingly by the Thick Coal. This seam, with a roof of black shale, 

 consists of 8 to 14 benches, resting directly on each other or sepa- 

 rated by thin partings of clay or shale. Each bench has its own 

 name and retains its character throughout the Thick Coal district. 

 At 2 miles north from Dudley there are eleven benches, with about 

 36 feet of coal, and partings, in all, amounting to 3 feet ; at i mile 

 east from Dudley it has 28 feet of coal in 12 benches and less than 

 2 feet of partings. The Top Slipper and the White, in upper part 

 of the seam, are the best house fuels, but next best are the Sawyer 

 and Slipper in the lowest fourth. The best coking coals are from 

 the Tow, below the top fourth, and the Benches at the bottom, both 

 of which contain much mineral charcoal. These are the conditions 

 near Dudley but changes appear quickly in exery direction. North- 

 ward, the Roof and Top Slipper pass off as a separate seam, the 

 Flying Reed, which, at Cosely, is 84 feet above the Thick, and at 

 Billston still farther north, the interval is 208 feet. The Flying 

 Reed thins away not far from Billston. The Thick and the Brooch 

 Coals are almost parallel in this area, the Flying Reed diagonaling 

 between them. The other benches of the Thick show a similar 



