﻿308 MR. R. KIDSXON ON THE DIVISIONS OF TEE [May I905. 



12. On the Divisions and Correlation of the Upper Portion of the 

 Coal-Measures, with special reference to their Development in 

 the Midland Counties of England. By Eobert Kidston, 

 F.B.S. L. & E., F.G.S. (Bead April 5th, 1905.) 



While working out the flora of the British coalfields, I have found 

 no group of rocks more interesting than the group of sandstones 

 and marls, frequently of a red, purple, or mottled colour, and their 

 associated limestones, which lie above the Middle Coal-Measures of 

 the Potteries Coalfield. 



When preparing my paper on ' The Fossil Flora of the Coalfield 

 of the Potteries,' 1 the classification which I adopted was that used 

 by Mr. John Ward, 2 but at that time little was known about the 

 thickness and stratigraphical relationship of the beds forming this 

 group. The classification adopted by Mr. Ward is as follows : — 



Permian Rocks 



f Red Marls. 

 \ Red Sandstone. 



1. Upper Coal-Measures. 

 | 2. Middle Coal-Measures. 

 ^ -r, 13. Lower Coal-Measures. 



Carboniferous Rocks { ^ Millstone -Grit. 



| 5. Yoredale Rock. 



^ 6. Carboniferous Limestone. 



In the present paper my remarks will be restricted to the rocks 

 here called Permian and Upper Coal-Measures. Any 

 reference that may be made to tbe underlying group will be merely 

 incidental. 



At the time when my paper on the fossil flora of the Potteries 

 Coalfield was written, I had seen no plants from the so-called 

 ' Permian' of that area, and, in regard to these rocks, Mr. John 

 Ward says, in the work already mentioned: — 



' I may here remark that a considerable development of red, purple, and 

 variegated marls which have been coloured by the Geological Survey as 

 Permian are, I am inclined to think, in reality Upper Coal-Measures.' (Op. 

 cit. p. 14 [sep. cop.].j 



That these rocks were Carboniferous and not Permian, I felt quite 

 certain : for, apparently, the same so-called ' Permian ' rocks were 

 passed through while sinking the shaft of the Hamstead Colliery 

 at Great Barr, near Birmingham • they contained a typical Upper 

 Coal-Measure flora ; and with this series I classed them at the time. 3 



1 Trans. Roy. Soc. Edin. vol. xxxvi (1890-92) pp. 63-98. 



2 ' The Geological Features of the North Staffordshire Coalfields, their Organic 

 Remains, their Range & Distribution ; with a Catalogue of the Fossils of the 

 Carboniferous System of North Staffordshire ' Trans. North Staffs. Inst. Min. k 

 Mech. Eng. vol.'x (1890) p. 4 [sep. cop.]. 



3 ' On the Fossil Flora of the Staffordshire Coalfields. Part I. On the 

 Fossil Plants collected during the Sinking of the Shaft of the Hamstead Collie ry, 

 Great Barr, near Birmingham ' Trans. Roy. Soc. Edin. vol. xxxv (1888-90) 

 pp. 317-35. 



