OE THE CARBONIFEROUS SERIES. 631 



(8) Warwickshire Coal-field. 



feet. 

 Stage G. — Sandstones and shales, with a band of limestone near the base, 



with Siyirorbis carbonarius* 60 



Stage F. — Sandstones, shales, coals, &c 1400 



Stage E. — Sandstones, shales, &c, with sheets of intrusive basalt 1500 



Stage D. Millstone Grit. — Converted into quartzite by sheets of intrusive 



trap 500 



Lower Stages C, B, & A not represented. 



The above concludes all that is necessary in order to show the 

 relations of the beds in the northern group of coal-fields of England 

 and Wales. With regard to the southern group, it will probably 

 be sufficient if we notice the Sections of Somersetshire and South 

 Wales. 



(9) The Somersetshire (or Bristol) Coal-field. 



It is very doubtful whether any representatives of the Stage G 

 occur either here or in South Wales. It is true that there is a local 

 subdivision of the Coal-measures into three stages in both districts, 

 of which the " Pennant Grit " forms the central member. This 

 arrangement is convenient for local purposes ; but the Pennant grit 

 can only be considered as an exceptionally thick group of sandstones 

 interposed amongst the Middle Coal-measures (Stage F), and not as 

 forming a central group corresponding to Stage F in other districts. 

 As regards the Lower Coal-measures (Stage E), although this stage is 

 remarkably well represented by its numerous marine fossils around the 

 rim of the South- Wales basin, it is less so in Somersetshire, partly 

 owing to its dislocated or inverted condition along the northern Hanks 

 of the Mendips, and also to the fact that it rarely crops out to the 

 surface, the beds being concealed by Triassic or newer strata. The 

 general section will therefore be somewhat as follows : — 



Section of the Bristol or Somersetshire Coal-field, 



feet. 

 Stage G. — Imperfectly represented. Possibly the upper part of the 



Radstock series , ? 



Stage F. Middle Coal-measures. — Shales, grits, and coals of the Far- 

 rington, Pennant, and Bedminster series. Fossils : plants, fish, and 

 Anthracosia 4700 



Stage E. Lower Coal-measures. — Sandstones, shales, and numerous coals 



of the Holcombe series (in part) 2000 



Stage B.~Millsto7ie Grit (Bristol) 950 



Stage C. — Yoredale Shales (thin) , 100 



Stage B. — Carboniferous Limestone 2S30 



Stage A. — Lower Limestone Shale , 100 



Old Red Sandstone. 



* Mr. Howell, "The Geology of the Warwickshire Coal-field," Mem. Geol. 

 Survey (1859). 



2t2 



