﻿Vol. 6 I.] TPPER PORTION OF THE COA' -MEASURES. 319 



Measure species are beginning to appear, and the species which 

 occur in the Middle Coal-Measures are gradually dying out. In such 

 a list as that tabulated on pp. 316-17, the mere names of species 

 do not fullj' represent this change ; the plants of the Middle Coal- 

 Measures become, however, rarer, not only in species, but in the 

 number of the individual specimens found ; and as these lower- 

 horizon forms become rarer in individual quantity, the Upper Coal- 

 Measure species become. more plentiful in kind and numbers. The 

 three subdivisions — the Newcastle-under-Lyme Group, the 

 Etruria-Marl Group, and the Blackban'd Group, represent, 

 therefore, a series of rocks, wherein the flora is a mixture of plants, 

 some of which are characteristic of the Upper Coal-Measures, while 

 others are characteristic of the Middle Coal-Measures. 



It is consequently impossible to class these rocks, either 

 with the Upper Coal-Measures above them, or with the Middle 

 Coal-Measures upon which they rest, as they form a distinct 

 botanical province, easily separated by their mixed association of 

 species. It was for this group that I originally used the term 

 of ' Transition Series V 



When this term was proposed, I did not know the important place 

 that this group would hold in the classification of the Upper Carbon- 

 iferous ; but, in recent years, the work of the Geological Survey 

 of Great Britain, as well as evidence obtained from mining opera- 

 tions, has shown the Transition Series to be a widely-extended 

 and important group, and one of great importance in determining 

 the position of the more valuable underlying coal-bearing strata of 

 the Middle Coal-Measures in our ' concealed ' coalfields. 



As, however, the term ' Transition Series ' is a somewhat in- 

 definite one, and naturally raises the question ' Transition between 

 what'? I propose to substitute the term Staffordian Series 

 for the inclusion of the Newcastle-under-Lyme Group, the 

 Etruria-Marl Group, and the Blackband Group of 

 North Staffordshire, as in that county these rocks have been worked 

 out more fully in detail than in any other area where they occur. To 

 Mr. Walcot Gibson we are largely indebted for the clear knowledge 

 that we possess of the Staffordian Series, though others have helped 

 in their elucidation, and of these, I would wish especially to refer 

 to the work of Mr. T. C. Cantrill in the Enville and Forest-of- 

 Wyre districts. 2 



For the Upper Coal-Measures 1 would propose the term Rad- 

 stockian Series; for the Middle Coal-Measures, Westphalian 

 Series, with which the flora of the Middle Coal-Measures appears 

 to agree ; and for the Lower Coal-Measures, the term Lanarkian 



1 Proc. Roy. Phys. Soc. Edin. vol. xii (1893-94) p. 228 ; also ' Additional 

 Records & ISotes on the Fossil Flora of the Potteries Coalfield ' Trans. North 

 Staffs. Field-Club, vol. xxxi (1897) p. 128. 



2 Quart. Journ. Geol. Soc. vol. li (1895) pp. 528-48. 



