ox MANOD AND TRE MOELWYNS. 383 



slato were numerous in the agglomerate, and lay in all directions, 

 a fact which indicates that they were cleaved prior to their inclusion 

 in the agglomerate, and sharp contortions such as might be ex- 

 pected on Prof. Hughes's theory were altogether absent. 



The Grarth Grit could be traced except for short distances, when 

 it is obscured by faults, all the way from Tyobry to Glanypwll, and 

 on the Manod side its relation to the beds above and below is the 

 same as that to the beds on the western side. At jSant-y-derbyniad 

 slate-quarry, near Llyn Serw, the Grit lies immediately upon Upper- 

 Lingula Flags containing Olenus scarabceoides, 0. spinutosus, and 

 Orthis lenticularis ; and still farther east, at Llechwedd-deiliog, there 

 are beds immediately overlying it containing JEcjliaa^ Or/i/(jia Sel- 

 wynii, and Pahearca, so that, as Sir A. llamsay has said, the 

 Tremadoc beds disappear altogether to the east. He had been 

 unable to find any traces of graptolites below the Garth Grit, and 

 he did not believe that there was in this district any other grit 

 which could be mistaken for the Garth Grit. 



