$ 
‘the same field, 
2066 
For the Monthly Magazine. 
An account of te MINERALOGY of the 
SOUTH-WEST PANT Of STAFFORDSHIRE. 
Abridged by JAMES KEIR, ESQ. F.R.S. 
(Continued from page 37 of this volume. ) 
Of the Strata or Measures between the 
Surface of the Ground and the Coal. 
AVING given a general survey of 
H the ceal- country, [shall now pro- 
ceed to amore detailed account of the 
sirata and substances under ground ; 
their regular situation; their irvegulari- 
ties of position, fractures, or fissures ; 
and whatever circumstances may seem 
to deserve most notice, in a mneralogi- 
cal view. The numbers and. thickness 
of the measures above the coal are so va- 
rious and different in diflerent. places, 
that they scarcely deserve. to be. consi- 
dered as regular strata, and have nothing 
of that uniformity which the beds of coal 
have, which are similar, at least ina very 
considerable degree, in. thickness, qua- 
lity, and regular position, over the ios inal 
extent of the counuy. The irregularity 
jn the thickness and number of measures 
above the coal, occasions a great differ- 
ence in the depth of the pits in different 
places. In some places the coal has been 
got at the surface of the ground, in open 
quarries, and im other fields the finer 
kind of clay, called. fire-clay, pipe-clay, 
and_ pot- -clay, from its power of resisting 
heat, and its fitness for making tobacco- 
Pipes and glass-house pois, are the next 
in order, with regard to uniformity and 
of thickness and position. «As to the 
other intervening masses of zeck, bind, 
clunch, and especially those upper earths 
which consist of red and yellow particles, 
they vary so much, and so regularly, 
that they frequeutly differ, not only in 
but even at the distance 
of a few yards, aud therefore no general 
account can be given of their order, 
number, or thickness. The kinds how- 
ever of the measures, are generally the 
same throughout the coal country, and 
of these a notion may be formed from 
the following listpof measures, found in 
drying a coal- pit in Tivedal colliery, in 
the parish of Rowley, 1797. 
yards feet inch 
4 Soil = - 1 0 
2 Brick clay = 1 8-6 
3 Brown coloured roach* a Cy gy 
4 Blue clay - OA Y@ 
* Roach is a ferruginous earth or clay, 
differently coloured, or “veined red and yellow. 
lt seems to me to consist of the decomposed 
partictes cf the basaltic rock, called here, 
Rowley rag,-of which the Rowley hills are 
termed, with other alluvial matt tole 
Mineralagy of the South W est of Reupondanire. 
FOct. I, 
ya:ds feet inch 
5 Red cokmrel roach LR? | 
6 Rock,with coal interspersed* 1 at eee 
7 Clunch, and iron stoneinitt 2 2 $ 
8 Smuttt oer yo cl ek iia 
co. WV nuke Chipeh «sok nae 
10 Grey clunch ~ a Tal 
11 Red wild stuff - 138 2 6 
12 Greenish rock tA pe ie 
138 Red wild stuff Cee Bap 
14 Binds with bails of gray rock,.3 2 0 
15 Wild stuff ty er 
16 Rocky black stuff . 0:4 5Q 
17 Smutt - Li 
18 Biack rocky stuff - Ye Re 
19 Kind clunch, with iron stone3 2 2 
20 Clunch beds a 4 0 0 
21 Soft elunch - 2 Bus 
22 ie O° 
Coai called the two-foot coal] 0- 
* The rock so eailed from its hardness, is 
white, and consists of a mixture of siliceous 
and argillaceous earths 5 which earths are 
mixed in d'fferent proportions. The rock has 
the largest proportion of siliceous earth, 
Next to this are the rock binds, which have 
more argillaceous earth, and are consequently 
softer than the rock. Then the clanch-bings 
have still less siliceous earth: and. lastly, 
clunch has the least of this latter earth; and 
is consequently the- seftest. The clanchy 
and clunch-binds, shiver into flakes, when, 
exposed to the weather, The rock-binds, 
and still better the rock, retain their texture, 
The rock is subject to cracks, or fissures, 
through which the water flows, and it is 
chiefly from these fissures in rocks, that the 
wat°rissues. Thin laminz of coal are often 
laid horizontally in the rock, and frequently 
there-is thin coal in the form of large broad 
leaves of aquatic plants, running in all dis 
rections through the rock. 
+ Clunch is a smooth, soft, earthy, mat- 
ter, which on exposure to the weather, falls - 
into shivers or flakes; it evidently consists 
chiefly of argillaceeus earth, and contains 
more or less of the silicious. I have not 
analyzed it, and therefore do not know more 
of its contents. Sometimes it has a reddish, 
or yellowish colour, and is then called by the 
colliers, qwild; but when it is of its proper 
bluish, or praia colour, it is s2id to be - 
kind; 6 which epithets the colliers express 
disk observation, that cual is generally found 
accompanied with clunch, and other mea- 
sures; they are of white, black, bluish, and 
gray, colours, but very seldom with such as 
are red or yellow. The former colours are 
therefore said to be kind, and the latter are 
called wild, as being irregular, or accidental. 
Clanch : -generally contains balls of iron- 
stone. : 
{ Smutt isa mixtureof coal and clunch. | 
} This thin coal (called two-foot coal, 
though seldom thicker than eighteen inches) 
it he first regular bed of coal. It is too thin 
to be of any use. ee <6 
; 23 Fire 
