STRATA OF SHROPSHIRE AND DENBIGHSHIRE. 17 



and afterwards by Mr. Binney*. It is an interesting section, com- 

 bining, as it does, the features of the strata on both the western and 

 eastern sides of the Xorth of England. Prof. Sedgwick says the 

 Magnesian Limestone of group 3, is the exact equivalent of the 

 Magnesian Limestone of Nottingham, Yorkshire, and Durham. The 

 same is true, he states, of the red marls and gypsums, while the red 

 sandstone of St. Bees Head, group 4, is unquestionably the exact 

 equivalent of the Upper Red Sandstone of those counties. The lower 

 part of the section, group 2, is more fully described by Sir R. I. 

 Murchison and Prof. Harkness in the paper already referred to. 



Section 5 takes us over to the eastern coast of England. It is 

 taken from the pit-section of the Monkwearmouth Colliery. It will 

 be observed that the same order prevails in group 3 as on the 

 western coast, except that here the limestone has thickened con- 

 siderably. Group 2 is represented bj* about 45 feet of red and grey 

 sandstones. Group 4 is not represented at all. This district is 

 more fully described in section 17. 



Section 6 brings us southward down the eastern side of England, 

 to the country around Leeds. It is given by Messrs Aveline, Green, 

 Ward, Dakyns and Russell f. The upper limestone is described as 

 grey, hard, and full of fossils. It contains little or no magnesia. 



The lower limestone is yellow in colour ; it decomposes readily 

 near the surface. It sometimes contains a hard flinty rock locally 

 known as " calliard ;" and, in places, its lowest beds are pebbly. Its 

 common fossils are Schizodus of three species. The interstratified 

 and overlying marls are red and variegated. They alternate with 

 beds of soft sandstone, which, in places, contain deposits of gypsum. 

 The authors describe these beds as slightly unconformable to each 

 other ; but they hardly mean to imply, I should think, that they 

 represent the three great divisions of the Permian strata. 



A more complete view of the Permian strata of South Yorkshire 

 is the following, given by Mr. J". "W. Kirkby J. 



Group 3 of Sections. 



Brotherton Lira est one and lower red marl and gypsum of 



Brotherton, Knottingley,Womersley,Wadworth, Tickhill,&c. 120 



Small-grained dolomite of the Yale of Went, Lound Hill, 



Cusworth, Leyit, Hagg, Boche Abbey. Warmsworth, &c. ... 200 



Lower Limestone of Pontefract, Wentbridge, Conisborough, &c. 120 



Group 2 of Sections. 

 Lower red, yellow, and variegated sandstone of Pontefract, 



ft. 



Hickleton, Cadeby, &o 100 



This section brings us nearer, geographically, to Section 7, which 

 shows the strata overlying the jSTottinghamshire coal-field. Group 

 2 is taken from the pit-section of the Shire-Oaks Colliery ; the red 

 and grey sandstones at its base are taken by local engineers to be 



* Mem. Phil. Soc. of Manchester, vol. ii. 3rd series, p. 373. 

 t The Gpology of the Carboniferous Bocks north and east of Leeds, 1870. 

 I " On the Permian Bocks of South Yorkshire, " Quart. Journ. Geol. Soc. 

 vol. xvii. p. 287. 



Q. J. G. S. No. 129. c 



