SKETCH OF THE GEOLOGY OF DERBYSHIRE. 7 
yd. ft. im 
Blues... 1 inper Hardieal yy... -scssncmmueeterascr ers» 1320 
IB IGU CLC: ceo «= 2.4 sonn ee opeeeetememeseeeces 180 0 0 
IBLowlie-</- 2, ee ain SOLE COAL Mc.” .5..227.0: sano meme ep ents ss jal Maes 
Bind pQses! R250. 0032. 0), SR eee cases *16 0 0 
Pinks: o2.5 Ss Deepithard\ coal 03. aver2. aspera ee Teel 
Bi Booths cde ones dene a 55 0 0 
MeL OW... 745, BUTNACE COAL .:. 5... coveseeecéees+ 0s <ceenedene anne ERT TY 
BING KCs ss escecccscos-raesbac.s 0st 02s sae 50 0 0 
Black ?......5. Clod coal, variable, average.................+.+- 200 
Birdy Keke 9s. ae. cheek 150 0 0 
———— 6. Buckland Hollow coal, or Morley Park 100 
TIE W, COM ly yaya c Mate hocwavccsaecslrcanuseee 
459 1 O 
A considerably greater thickness exists, but these are the beds best 
known. The upper hard coal lies at a depth of 37 yards in the 
neighbourhood of Ripley, while in the Shipley basin it has a depth of 
60yds., both these places being rather on the western side of the coal- 
field, and shewing, therefore, how narrow it would be hereabouts were 
it not for the effect of the anticlinal line, since on the E. side of the 
coal-field the magnesian limestone rests almost immediately on this 
same coal. 
If now, disregarding the minor variations, we look to the general 
dip of the coal measures, we shall find it to be to the E. till after a 
certain distance they are covered in that direction by the overlying 
magnesian limestone. The boundary of this formation will be marked 
on a map by a line drawn from Pebley Inn, in the N.E. of the county, 
round the W. side of the village of Barborough, and thence nearly 
due S.to Bolsover and Hardwick Hall. Here it enters Notting- 
hamshire, and proceeds, with a very irregular outline, by Teversal, 
Sutton and Kirkby in Ashfield, Annesley, Watnall, and Nutthall, to 
Strelley. From Strelley the line turns to E. by Bilborough to Rad- 
ford. Along all this line the coal passes, with an easterly inclination, 
under the magnesian limestone, which has likewise a dip to the E. 
and thus, at first sight, the two formations appear perfectly regular 
and conformable. Upon an enlarged examination, however, this will 
be seen not to be the case. In the first place, the angle of dip of the 
coal measures sometimes varies, while that of the magnesian limestone 
* This thickness increases towards the west to more than 30 yards. 
VOL. IX., NO. XXV. a 
