Pig, 6. — Comparative sections illustrating the relation of the 

 sequence north-east of Aberllefenni with that at Plynlimon. 



PLYNLIMON 



Zone of Glyptograptus persculptus 



N.E. OF ABERLLEFENNI 



Zone of Glyptograptus 

 persculptus 



Garnedd-wen 

 Beds 



Narrow Vein 



Dicellograptus anceps- 



Red 



Vein 



Dicellograptus anceps. 



Orthograptus truncatus 



var. abbreviatus 



Orthograptus 

 truncatus 



| Vertical scale : 1 inch =800 feet.] 



