168 



solves, on being immersed in water, or even on exposure to the air, 

 into a fine soft clay. It contains a portion of bituminous matter, 

 and generally has an unctuous feel, on which account the Scotch 

 colliers term it creeshy blaes or greasy blaes. 



Not only do these strata vary in different districts, but, even in the 

 same district, a considerable difference will sometimes be found in 

 the strata ; and these differences may even arise from varieties fre- 

 quently occuring in the same species of strata, from which may result 

 several distinct strata, differing in colour, quantity, coherence, &c. 

 whilst a stratum of another kind may occur only once or twice. 



The following Example of the different Strata of Earth, Stone, and Coal, in a Coal Mine 

 to the West of Dudley, in the County of Stafford, will serve to give you an idea of the 

 manner in which they occur. 



Strata. Ft. 



No. I Yellowish clay, immediately under the mould 4 



2 Bluish clay 5 



3 more compact and firm, called clunch, and bearing the impression of plants . 24 



4 softer than No. 3 9 



5 A bank (stratum) of grey stone 4 



6 Whitish yellow clay 21 



7 Hard grey rock, with faint impressions of vegetables 75 



8 Clunch, in which fossil plants are found 5 



9 Bench or bank coal (black and glistening) 1 



10 Slipper coal (abounding with coals) 3 



11 Spin coal (a blacker and glossy coal) 4 



12 Stone coal (pretty like Cannelcoal) 4 



These four beds were separated by BATS, a hard stony earth 1 



13 Dunrowbats j 



14 Grey iron-stone, called grey-bench 1 



15 Bluish bat, in which is found iron-stone 3 



16 Blackish and hard iron ore, called white-row grains, the grains being like shot I 3 



1 7 Hard grey iron mine, spotted with white, called mid-row grains 2 



1 8 Gubliu bat, a black fissile substance, an iron ore, in which a bituminous shivery earth 



abounds 2 



] 9 Gublin iron-stone (an iron ore, hard, blackish, and spotted with white) 9 



20 Bat, lesembling No. 18 1 6 



21 Canuoc iron-stone, hard and grey 6 



22 Bat, somewhat harder than No. 20 1 



23 Rubble iron-stone, in grains, grey and hard 6 



24 Table bat 2 



25 Foot coal, a coarse sort 1 



26* Bat, black, brittle, and glistening 6 



27 Heathencoal 6 



28 Bat coal, an ordinary coal, in a thin bed, and doesjot bum well i 



29 Bench coal 2 



30 Bat 6 



180 6 



