680 



MISS E. M. E. WOOD ON THE 



[Not. 1906, 



of a mile consist of thickly-bedded, dark-blue, concretionary mud- 

 stones, with thin shale-partings. These are probably the highest 

 beds that can be referred to the Brj'nmair Group ; but no fossils 

 were obtained from them at this locality. 



Fig. 5.— Sketch-Plan 



of the 



DOLGADFAN LOCALITY. 



Scale of Yards 



"^i 



\ 48°* * Ac2 58^ :; 



Ba - Brynmair Beds 



Ba2. Upper part 



Bai. Lower part 

 Ac - Tvvymyn Beds 



Ac2.Zone of M. Sedgwickii 



Ac 1. Grey barren mudstones 

 Ab - Dolgadfan Beds 



Zone of M. co/wolufus 



In descending the river, the low dip of the beds is seen gradually 

 to change ; and, in the neighbourhood of a small footbridge fully 

 400 yards below Bont-y-Green, the strata, which here consist of 

 banded grey shales, small flags, and soft dark mudstones, are either 

 vertical in position or dip south-eastward, and show evidence of 

 faulting and disturbance. A few yards west of the footbridge 

 some fragments of graptolites were obtained from one thin, dark, 



