480 



MB. 0. T. JONES OX THE IIAKTFELL-VALENTIAX 



[Nov. 1909, 



sandy character contrastingly strongly with the underlying beds. 



In them I found Monograptus rheidolensis and Climacograptus sp.. 



At the bend where the 



Fig. 5.— Plan of the Fuches-gau locality, roa d-section terminates, a 

 on the scale of 12 inches to the mile. bedding-plane is exposed 



which is covered with a 

 matted aggregate of Mono- 

 graptus atavus, sp. nov. 



On the slope leading- 

 down to the valley east of 

 the road are a few expo- 

 sures of soft, blue, massive 

 mudstones and flags. Close 

 beside the stream, a band, 

 of cleaved shale in them 

 yielded (F. 6) Monograptus 

 triangularis, M. communis, 

 M. revolutus (?), M. cf. 

 fimbria tus,M. gregarius (?), . 

 M. attenuatus (?), and 

 abundance of Climacograp- 

 tus tornquisti. About 20 

 yards away on the east 

 side of the valley pale 

 greenish mudstones, simi- 

 lar to those near Eisteddfa 

 Gurig (p. 478), are ex- 

 posed. 



This section confirms 

 the previous one as regards 

 the relation of the Diplo- 

 graptus Beds to the unfos- 

 siliferous Bryn-glas Mud- 

 stones, the oncoming of 

 strata with Monograptus, 

 and the marked change 

 from the dark-blue shaly 

 type of sediment to the 

 pale greenish mudstones ;.. 

 moreover, a glimpse is ob- 

 tained of the rocks im- 

 mediately underneath the 

 latter, which were con- 

 cealed in that section. 



From the syncline to 

 the west of Craig Tspio, 

 the base of the Eisteddfa 



Beds strikes steadily southwards, and passes behind the Dyffryn 



Castell Hotel. Characteristic graptolites were obtained at several. 



