﻿To face p. 244.1 



Quart. Journ. Geol. Soo. Vol. LXI. PI. XXVIII. 



ZONES 

 SUBZONES 

 HORIZONS 



M 



Clei 

 a K t 



R/ 



K 2 



>,NGE 

 Za 



DlAGR^ 



phrentb 



z 2 



M OF COf 



Syringothyris 



" c 



IALS IN THE 

 S 



s, 



Bristol Area 

 s 2 



Dibunopliyllum 

 D, D 2 



e 



Alveolites 

























, . ' 



















'-' 



































Of. ,„*„„„„,<: 























, , ■ 









— 















Zaphrclis 

























' 

















z.»w™«™ 





















































































Cgathoplwllitm 















U 





-w— 































-e- 



C 1 II 











































Dilumoplnillum 









































Cyclopliyllum ,{■ 





















^ 



Axoptiyllum ,(■ 









































