78 



SECTIONAL ADI>RESSES. 



Grit {sensu lato) to the underlying strata. In briefly considering this 

 subject the following regional diAnsion is most convenient, A-iz. : — 



1. West of England. 



2. Sonth Wales. 



3. North Wales, Midlands and Northern Counties. 



West of England (see fig. 2). 

 In the West of England, as is well known, ' jMillstone Grit ' conditions 

 set in at a progressively lower level as one passes northwards from the 

 Bristol area. Thiis in the Avon section ^^ and in the Mendips they set in 

 at the top of D.^. At Sodbury, where the section is incomplete, 84 ft. 

 of Dj limestones are exposed, but in the Wickwar cutting''' a few miles 

 to the north the early advent of ' ilillstone Grit " conditions reduces the 

 limestone to 55 ft. In the Tji:herington district ^^ and in the Chepstow 

 area Millstone Grit conditions set in at the top of S.,. In the Forest of 

 Dean the Drybrook sandstone (jMillstone Grit of earlier authors) is probably 



Mendipa and 

 Avon Section. 



Wickwar. 



Tytherington 

 and Chepstow. 



Forest of 

 Dean. 



Cloo. 



Do 



Di 



■iA s 



o a 

 2,3. 



b c 



O cj 



K K K K K 



Fig. 2. 



Table showikg the Level at which Sandy Co^'DITIONS set in at 

 Certain Localities in the South-west Province. 



{Not to scale.) 



»« Q.J.O.S., vol. Ixi. (1905), pi. xxvii. 



»^ Proc. Bristol Nat. Soc, 4th Ber., vol. vi.. pt. 3 (1926, issued for 1925), p. 242. 



»• Ibid., pt. 1 (1924, is8u«d for 1923), p. 64. 



