68 



SECTIONAL ADDRESSES. 



Vaughan's earlier 

 usage. 



'a 

 o 

 t> 

 <1 



Dibunophylluui 

 zone 



Seminula 

 / zone 



Lower 

 'Millstone Grit' 



Base_o y of Visean 



'a 



'a 

 a 



Syringothyrie 

 zone 



1 1- 



1 a ' 



Zaphrentis 

 zone 



Cleistopora 

 zone 



Modiola 

 phase 



Base of Tournaisian 



D, 



Di 



s.; 



Si 



Y 

 Z2 



Zi 



Ka 



Ki 



Vaughan's later 

 usage. 



Top of Visean 



Belgian 

 equivalents. 



M 

 O.R.S. 



Base of Visean 



,--0) 



C, 



Ci 



Cleistopora 

 zone 



Base of 

 Tournaisian 



a 

 .2 



'5 

 ■ c 



§ 



EiG. L 



Table showing the Subdivisions of the Avonian Rocks in the 

 South-western Province and thetr Equivalents in Belgium. 



