Vol. 57.] UPPER COAL-MEASURES OF THE MIDLANDS. 251 



17. Gn the Character of the Upper Coal-Measures of North 

 Staffordshire, Denbi&hshire, South Staffordshire, and 

 Nottinghamshire ; and their Relation to the Productive 

 Series. By Walcot Gibson, Esq., F.G.S.' (Read March 20th, 

 1901.) 



OOKTENTS. 



Page. 



I. Introduction 261 



II. North Staffordshire 253 



III. Denbighshire 260 



IV. South Staffordshire 261 



V. Nottinghamshire 262 



VI. General Summary 264 



VIT. BibHographical List , 265 



I. iNTRODrCTION. 



The productive measures in the Midlands are succeeded by a con- 

 siderable thickness of strata, barren of workable seams of coal. 

 The study of these higher strata has, in comparison with that 

 given to the coal -bearing portion of the Carboniferous, been 

 neglected, though they early attracted the attention of Murchison,'^ 

 Prestwich,^ and Phillips.* By these and subsequent observers, 

 the presence of thin bands of impure limestone with Spirorhis 

 was considered to characterize the series. It has also been 

 generally recognized that while the predominating colour of the 

 productive series is grey, that of the overlying barren series is red; 

 but, with the exception of Beete Jukes ^ and D. C. Davies,^ no 

 definite sequence has been even suggested. Presh interest was given 

 to the study of these strata by the discovery that the fauna and 

 flora of the immediately overlying red beds, or ' Salopian Permian,' 

 possessed a Coal-Measure facies, and that it would be more natural 

 to include them in the Carboniferous system. Recently it has been 

 stated, in two papers,'^ that the higher Coal-Measures are strongly 

 unconformable to the underlying productive series. 



The object of this paper is to show that in four widely-separated 

 areas a definite lithological sequence may be distinguished in the 

 higher Coal-Measures ; that the relation of the upper to the 



1 Communicated by permission of the Director of H.M. Geological Survey. 



^ ' Silurian System ' 1839, pp. 81 et segq. 



3 * On the Geology of Coalbrookdale ' Trans. Geol. Soc. ser. 2, vol. v (1840) 

 pp. 428 et segq. 



* Mem. Geol. Surv. vol. ii (1848) pt. i. 



'= Mem. Geol. Surv. ' South Staffordshire Coalfield ' 2nd ed. (1859). 



® Quart. Journ. Geol. Soc. vol. xxxiii (1877) p. 10. 



"^ T. T. Groom ' On the Geological Structure of Portions of the Malvern & 

 Abberley Hills' Quart. Journ. Geol. Soc. vol. Ivi (1900) pp. 138-95, & W. J. 

 Clarke ' The Unconformity in the Coal-Measures of the Shropshire Coalfields' 

 ilnd. vol. Ivii (1901) pp. 86-95. 



s2 



