[To face p. 524. 



REFERENCE 



Old Red Sandstone. 

 Bala. 

 WMMik Dicranograptus Shale 



_^~J g\ Parc-y-berllan CvmOernant ') 



I. ' Didymograptus Murchispni Shales. 



'■^A Didyinograptus Bi/idus Shales. 

 A re nig. 



Treviadoc Slates. 

 Alluvium. 



-'Faults. I \ Dips. 



..^Fossil Localities. I 



;:Ty-newydd 





[f^^Qfnrr'nj 



+\ 3G Merlins , 



