Page:The South Staffordshire Coalfield - Joseph Beete Jukes - 1859.djvu/38

											FT.		FT.
19.	(I. 6.)			Intermediate measures containing, at Bentley, the ironstones known as the Lambstone and Brownstone						from	10	to	33
20.	(I. 7.)			New Mine or White ironstone						from„	2	to	10
21.	(I. 8.)			Measures containing the Penny-stone ironstone called also Bluestone or Cakes						from„	10	to	25
22.	(XIX.)			Sulphur coal						from„	2	to	9
23.	Intermediate measures									from„	3	to	99
24.	(XX.)			New Mine coal[1]						from„	2	to	11
25.	(I. 9.)			Measures containing the Fireclay Balls ironstone occasionally						from„	2	to	40
26.	(XXI.)			Fireclay coal (and partings)						from„	1	to	14
27.	Intermediate measures									from„	2	to	10
28.	(I. 10.)			Getting Rock ironstone (occasional)						from„	4	to	5
29.	(I. 11.)			Poor Robin ironstone measures						from„	3	to	5
30.	Intermediate measures, sometimes wanting									from„	0	to	9
31.	(I. 12.)			Rough hills White ironstone (occasionally)						from„	2	to	19
32.	(XXII.)			Bottom coal						from„	3	to	12
33.	Intermediate measures									from„	5	to	30
34.	(I. 13.)			Gubbin and Balls ironstone, sometimes called the Great or Bottom Gubbin						from„	3	to	10
35.	Intermediate measures									from„	18	to	50
36.	(XXIII.)			Singing or Mealy Grey coal (occasional)						from„	2	to	4
37.	Intermediate measures									from„	16	to	50
38.	(I. 14.)			Blue Flats ironstone						from„	2	to	9
39.	Intermediate measures									from„	10	to	14
40.	(I. 15.)			Silver Threads ironstone						from„	4	to	7
41	Intermediate measures									from„	6	to	15
42.	(I. l6.)			Diamonds ironstone						from„	2	to	3
43.	Lowest measures, maximum thickness known below the Diamonds ironstone										about		50

The variations in thickness, noted in the preceding general section do not take place indiscriminately, but chiefly according to a general rule, the least thickness being almost invariably found to the south, while the greater thicknesses come in regularly as we proceed northwards. There are, however, local exceptions to this statement, in the fact of a sudden thickening or thinning of any particular group of beds in a partial manner, and over a small area, with an immediate return to the normal thickness of the neighbourhood. The group of sandstones known as the Thick-coal rock, and some other sandstones, have these partial thickenings, while the shales between the New Mine and Fire-clay coals, sometimes, as in the Stowheath field, diminish quite unexpectedly to two feet, and then suddenly regain their usual dimensions of 30 or 40 feet. Sometimes, indeed, these two coals are so split up by partings, that when the thickness between

---

1. The New Mine coal is completely separated into two coals at Bentley, there called the Three-foot and the Five-foot, with 33 feet of shale and sandstone, containing ironstone between them.