"Vol. 69.] SERIES OF THE SOUTH STAFFORDSHIRE COALFIELD. 435 



The different opinions arrived at by successive investigators 

 appear to result from the order of their researches: those who 

 describe the local descending sequence have carried boundaries 

 downwards ; while those who describe the ascending sequence have 

 removed them upwards. The cause of this difference of opinion 

 is stated by Murchison as follows : — 



'The mere lithological character of many of these beds might still mislead 

 the most practised geologist, if he had not worked out the relations of all the 

 other rocks of the district.' 1 * 



He adds elsewhere (p. 5G) : — 



' It appears, therefore, that between Hagley and Halesowen there are all 

 the proofs of a Lower New Red Sandstone .... passing down into Carboni- 

 ferous strata so gradually, that it is difficult to draw the line of separation, or 

 define it with any accuracy upon a map.' 



Dr. Walcot Gibson has, however, accomplished a work of great 

 importance in correlating the sequence of Upper Carboniferous 

 rocks in South Staffordshire with that of North Staffordshire, 

 Denbighshire, and Nottinghamshire. 2 The importance of this step 

 was foreseen by Jukes himself, and the work was apparently con- 

 templated by him, though never carried into effect. In September 

 1847, in a letter to Ramsay, 3 he wrote : — 



' I look upon the Bridgenorth and Bewdley coalfield, and that between 

 Coventry and Tamworth, as the districts to enlighten us on the true 

 relations between the Coal Measures of [sic] Y.R. (that is, Young Red, or 

 Permian and Trias).' 



He urges the need for 



' the thorough working out of the midland districts, and comparison between 

 north and south, tracing the marine and freshwater beds, etc' 



In February 1848, also writing to Ramsay, he says : — 



' I hold .... the North Staffordshire coalfield to be the only one in Britain 

 where the whole series of CM. can be proved to exist. I'll draw out the case 

 more at length in future.' 



The correlation effected by Dr. Walcot Gibson is as follows : — 



Bed sandstones and 

 marls. 



North South 



Staffordshire. Staffordshire. 



(4) Keele Series. Keele Seines. 



. (3) Newcastle -under-Lyrne ] Halesowen Series _ f Grey sandstones and 



Series. J [ shales. 



(2) Etruria Marl Series. { ' ^° H^iTs CkyS ' } ^T^ "^ *"** 

 (1) Blackband Series. (? absent) 



The Blackband Series is probably absent from the South Stafford- 

 shire Coalfield. The term ' Red Coal-Measure Clays ' adopted by 



1 ' The Silurian System ' 1839, pp. 55-56. 



2 Q. J. G. S. vol. lvii (1901) fig. 2, p. 263. 



3 ' Letters & Extracts, &c. of J. B. Jukes— Edited by his Sister ' London, 

 1871, pp. 320, 321, & 346. 



