Quart. Journ. Geol. Soc. Vol. LXII. Pl. XLVI. 



A saphtis - tyr annus 

 beds. 



Lidymograptus- bifidus 

 beds. 



\ Llandeilo (ctd.) 

 Didymograptus-Murchisoni 



Llanvirn. 



\ Tetragraptus-shales. 



Ash, grits, and 



conglomerates. 



J Tetragraptus-shales 



Blue-grey mudstones, 

 etc. 



Old Red Sandstone. 



Arenig. 



} . 



