136] 



A TOPOGRAPHICAL 



The main coal consists of divisions, and indeed is a number of 

 beds, differing regularly in quality and thickness, and separated 

 by very thin partitions, which are sometimes wanting ; so that it 

 is generally named as a single bed of coal. These divisions, with 

 their thickness, are as follows : 



Feet In.j 



1. Roof floor, top floor, (Dr. 



Plot,) 4 



2. After a parting of 4 inches 



of soft and dark earth 

 top-slipper ; over-slip- 

 per, (Plot,) 2 2 



3. Jays, 2 



IFhite stone, called Patchel, \ inch. 



4. Lambs, 1 



5 Tough kitts, or heath, .... 1 6 



6. Benches, 1 6 



7- Brassils or corns, 1 6 



Foot coal parting (sometimes only) 



Thickness, 



13 8 



Feet In. 

 8. Foot coal, or bottom slipper 1 8 



John coal parting 1 inch. 

 9. John coal, or slips or veins, 3 

 Hard stone 10 inches, or less. 



10. Stone coal, or long coal,. . 4 



11. Sawyer, or springs, 1 6 



12. Slipper, 2 6 



Humphrey parting. 



13. Humphreys, or bottom- 



bench Omfray floor, 

 (Plot,) 2 3 



Total main coal, .... 28 



The coal, including the partings, which vary in thickness, gene- 

 rally exceeds ten yards. A very extraordinary variation occurs 

 in one instance ; the two upper beds of the main coal, namely, 

 roof, floor, and top slipper, separate from the rest of the coal at the 

 Bloomfield colliery, and the separation grows wider and wider, in 

 a northern direction, till at length those two beds which, when 

 thus separated, acquire the name of the flying reed, crop-out to 

 the surface, and are lost, whilst the lower part of the coal proceeds 

 on to Bilston, where consequently it has only the thickness of 

 eight yards. 



The interval between the flying reed and the main coal, is filled 

 up with soft clunch at the place of separation, which by degrees 

 assumes a harder texture, and changes to a rock that will strike 

 fire with steel. 



The measures which are generally known, under the main 

 coal, which in some places are dug for the sake of the iron-stone 

 and glass-house pot-clay, and sometimes for the sake of the 

 coal called heathing coal, are as follows ; but here it may be ob- 

 served, that the main coal is not in such places at so great a depth 

 from the surface as in the instance heretofore given : 



