270 Reviews — Geological Survey — Derby and Notts Coalfield. 



Limestone shales, here only between 400 and 500 feet thick. This 

 term has been adopted for this map to replace the Yoredales of the 

 previous edition, though the reasons given for adopting a different 

 nomenclature for this sheet than was selected for the maps and 

 explanatory remarks of Sheets 123 and 110 are somewhat ambiguous 

 and not obvious. However, the important fact remains that the 

 ' Limestone shales ' are recognised to be the equivalents of the 

 Pendleside Series elsewhere. Albeit ' Limestone shales ' is somewhat 

 of a misnomer, because the shales have no faunal connection -with the 

 limestone deposit, and the amount of limestones found in the shales are 

 only 2 or 3 per cent, of the total. It is, however, non-committal, and 

 gives an opportunity for hedging later if found necessary, and it will 

 be interesting to watch what line is taken in the sheet further north 

 Avhich will not be so far awaj^ from the type district. 



The chapter on the Millstone Grits is important. These beds are 

 thinning and dying out, and the stratigraphy presents difficulties of its 

 own. It is interesting to note the presence of Glyphioceras hilingue 

 above the Kinderscout Grit. This goniatite appears to characterise 

 the upper part of the Pendleside Series and to persist in Lancashire as 

 high as the Sabden shales. The chapters on the Coal-measures are 

 from the pen of Mr. Walcot Gibson, and are excellent and full of 

 detail. He has been careful to chronicle the occurrence of the fossils 

 connected with each bed of coal, both plants and mollusca, and he 

 finds that the distribution of the Lamellibranchiata reveals a general 

 sequence similar, in the main, to that found to obtain in the North 

 Staffordshire Coalfield. He attempts a certain amount of correlation 

 between the Derbyshire and North Staffordshire Coalfields on palseonto- 

 logical data. As in North Staffordshire, certain marine bands have 

 been discovered which "will afford great help in fixing horizons, 

 e.g. the Alton coal is considered to be the equivalent of the Crabtree 

 of the Cheadle and Pottery Coalfields. Between the Coal-measures and 

 the Permian series is a great unconformity, and this opens up a large 

 question, as to what was the condition of things on the west side of 

 the Pennine axis which prevented Permian rocks being laid down in 

 Cheshire and Staffordshire. 



The Triassic rocks are found not much to exceed 800 feet in thick- 

 ness, and apparently all the members, which measure several thousand 

 feet thick in Cheshire, are represented. 



It is noted on p. 126 that the Bunter gravels contain pebbles with 

 Silurian fossils similar to those found in Staff'ordshire. 



Chapters on folds and faults, the superficial deposits, and economic 

 geology are also included. It is curious that no Chalk flints have been 

 definitely recognised in the drift ; these erratics are very common 

 further west at Barrow Hill, Eocester, and at Abbotts Bromley. 



An appendix gives a detailed section of the shaft at Kilbourne 

 Colliery, with the fossils found at each depth. 



The authors are to be congratulated on the excellent volume they 

 have produced. At last a memoir dealing with a colliery district has 

 palteontological details put in a form which will be useful to the 

 mining engineer who can appreciate them. "VVheeltok Hind. 



