A HISTORY OF NOTTINGHAMSHIRE 



These sections taken together afford a fairly complete view of the 

 development of the Coal-Measures in the county. On comparing the 

 thicknesses of the strata between well known seams there does not appear 

 to be quite so great a constancy as is claimed in Yorkshire. 



Possibly the seams called by the same name in different collieries are 

 not always exactly on the same horizons. One may die out and 

 another take its place above or below it. The total thickness will vary 

 according to the sections selected for addition, but if there are added 

 together 536 feet for the Upper Measures at Thurgarton, 1,250 feet for 

 the Rotherham Red Rock to the Top Hard coal at Shireoaks, 584 feet 

 to the Piper coal at Clifton, 678 feet to the Kilburn coal at Lodge 

 Colliery, and 476 feet for the measures at Ruddington boring, which 

 commences below the Kilburn coal we obtain a total of 3,524 feet. 

 Considering this great thickness, and that there is no sign of thinning 

 out on the east side of the county, nor of the assumption of a westerly 

 dip, there cannot be a doubt that the whole of Nottinghamshire, with 

 the exception of a narrow band along its southern margin, is underlaid 

 by Coal-Measures, mostly at less than the maximum depth of working, 

 and these measures may extend also to any distance beneath Lincolnshire 

 and perhaps even the German Ocean. 1 



Regarding the Coal-Measures of Great Britain as a whole 

 geologists have divided them into three series, Lower, Middle and 

 Upper. The Lower Series, where characteristically developed, are dis- 

 tinguished by containing abundance of marine fossils, and by some of 

 their coals having a seat earth of siliceous gannister instead of clunch. 

 Such are principally found in the northern coalfields. The Middle Series 

 are more entirely freshwater in origin and contain abundant coal seams 

 with nodular bands of ironstone in all the midland coalfields. The 

 Upper Series contain many ironstone beds and ironstained red shales with 

 no workable coals, or very few, in the northern part of their range, but 

 form very rich coalfields in the southern. These divisions correspond 

 to changes in the accompanying plant remains, and possibly indicate also 

 that conditions favourable to coal-growth gradually advanced from north 

 to south. 



The geographical position of Nottinghamshire, near the centre of 

 the English coalfields, prepares us for the statement that the greater 

 part of its coal-bearing strata belong to the Middle Series. No gan- 

 nister beds as above defined are known to come nearer to Nottingham 

 than Crich. We must necessarily however call those beds Lower Coal- 

 Measures that intervene between recognized Middle Coal-Measures and 

 Millstone Grit even in ignorance of their possessing such characteristics. 

 In this case the line between these and the Middle Series must be chosen 

 from considerations elsewhere derived. It is by the Geological Survey 

 drawn for convenience below the Black Shale, Clod or Silkstone coal, 

 which is widespread and constant. All the beds below these are there- 



1 See Dunstan, loc. cit. 

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