456 Notices of Memoirs — British Association — 



(5) On the Correlation of the Leicestershire Coal-field. By 

 KoBERT DoxTGLAss Vernon, B.A., B.Sc, F.G.S. 



rilHE following is a preliminary account of a study in the 

 JL correlation of the coal-fields of the eastern portion of the great 

 Midland coal basin. The area in question includes the Derbyshire 

 and Nottinghamshire Coal-field in the north, the Warwickshire 

 Coal-field in the south-west, and the Leicestershire Coal-field, which 

 lies midway between the two. It is with the latter that we are here 

 chiefly concerned. The Carboniferous rocks of Leicestershire include 

 Carboniferous Limestone, Limestone Shales, Grits, and Sandstones 

 that have been referred on lithological evidence to the Millstone 

 Grits, and, lastly, the Coal-measures. Such a sequence at once 

 suggests a correlation with the Derbyshire and ^Nottinghamshire 

 type, but the presence of unusually thick seams of coal which split 

 towards the north favours a comparison of the Middle Coal-measures 

 of Leicestershire with those of Warwickshire. Finally, in the 

 complete absence of the Transition Series and. Upper Coal-measures 

 and the presence of a complex fault system, the Leicestershire Coal- 

 field stands quite apart from either of its neighbours. 



For the detailed correlation of the Upper Carboniferous of these 

 tectonic basins we have several independent criteria, both ]iliysical 

 and palaeontological, but strong theoretical objections may be urged 

 against the use of physical criteria alone, and in practice it was found 

 to be impossible to use either the important sandstones or the seams 

 of coal in the correlation even of the eastern and western portions of 

 the Leicestershire Coal-field itself. 



The problem was then attacked from the palaeontological side. 

 Fossil plants proved of relatively little value in the subdivision of 

 the Leicestershire sequence, because the lowest and the highest 

 plant-bearing horizons both appear to fall within the Middle Coal- 

 measures. The freshwater lamellibranchiata ( Carhonicola and its 

 allies) were equally unsatisfactory, so that the work finally resolved 

 itself into a search for Marine Beds and an attempt to lay down their 

 outcrops on the 6 inch maps. 



Of the three more or less distinct districts into which the Leicester- 

 shire Coal-field may be divided, the Central or Ashby area of so-called 

 unproductive measures yielded no fossils, either plant or animal, and. 

 the age of the beds, whether Lower or Middle Coal-measures, remains 

 an open question. The Eastern or Cole Orton area presents serious 

 difficulties to the collector, being for the most part a concealed coal- 

 field worked under a thick Triassic cover, and the results obtained 

 were merely of local interest. Attention was finally concentrated on 

 the western or Moira area, where the sequence is more complete than 

 in the rest of the coal-field, and exposures are much more numerous. 

 Many fossiliferous horizons were discovered, which yielded a rich 

 flora, several rare Crustacea, some fragmentary fish-remains, numerous 

 freshwater lamellibranchiata, and above all an abundant marine fauna 

 from several different horizons and many localities. Unfortunately, 

 no indication of the well-known Ganister Coal Marine Bed (Alton 

 Coal of Nottinghamshire) has yet been found in Leicestershire. 



