( 543 ) 
XXX, A Bat under the laft, and is as low (viz. i88i 
Feet) as they generally dig, tho’ there is a coarfe Coal 
under this. 
r * r . 4 f - - - ,-•> - - ** 
N. B. Thofe Subftances, which divide the Strata of 
Coals and Iron Oars from each other, are called Bats 
by the Miners : They are generally black, confiftihg of 
a Matter peculiai to themfelves, and are ot a Texture 
neareft like Marie $ tho’ fome of them are fiffile, and 
others have a Subftance nGt unlike Coal mixt with 
them. 
A Table of the Thicknefs 
tion to Water-) 
of each Stratum, and its Bropor* 
or Specific^ Gravity. 
Number of 
Thicknefs of 
Proportion to 
Or Specifick 
the Strata. 
each Stratum. 
Water, 
Gravity. 
Feet. 
inches. 
I. 
4 
O 
as 585 to 192 
as 200 to 
ir. 
5 
0 
296 
l68 
176 
hi. 
24 
0 
23 
9 
256 
IV. 
' 9 
0 
209 
106 
197 ‘ 
V. 
4 
0 
5 s ? 
2 37 
246 
VI. 
21 
0 
401 
192 
209 
VII. 
7 S 
0 
6 83 
2 59 
243 
VI IT. 
5 
a 
23 ? 
_ IL 
_? S 3 . 
VIII+. 
1 
0 
— 
IX. 
3 
0 
7 
5 
140 
X. 
3 
0 
106 
72 
[ *47 
XL 
4 
0 
l V 
114 
129 
XII. 
4 
0 
185 
143 
130 
XIII. 
1 
0 
408 
198 
r 306 
XIV. 
0 
1 
204 
67 
! 3°3 
XV. 
0 
3 
,8j 
72 
2 54 
XVI. 
1 
3 
325 
232 
3 34 
XVII. 
0 
2 
7S1 
2 44 
1 3 2 ° 
