12 dr. J. e. marr os the LOWER [March 1913, 



"Wen lock Beds. — The graptolitic succession of these heds has 

 recently been described by Miss "Wataey & Miss "Welch, 1 and no 

 further remarks are necessary concerning the graptolites. Other 

 fossils are rare, save some obscure brachiopods and cephalopods ; 

 but my son discovered the head of an Arethusina in an exposure 

 of the Cyrtograptus-murcMsoni Zone of Middle Gill. (See Appendix, 

 . P- 16.) 



Lower Ludlow Beds. — Here again, the graptolitic succession 

 has been described by the above-named authors, who note the 

 occurrence of the Phacops-obtiisicaudatus Beds. In these beds 

 a fairly rich fauna has been discovered, including the following 

 fossils : — 



Acidaspis. 1, 2. Phacops sp. 1. 1, 2. 



Encrinurus variolaris Brongn. Tar. ? Phacops sp. 2. 1 . 



2. Leptana. 1, 2. 



Proetus. 1, 2. Orthis. 1. 



Phacops obtusicaudatus Salt, (common Ortkoceras, various species (frequent), 

 wherever the beds are exposed). 



l=JTorth-nort]i-west of Narthwaite. 



2=River Rawtbey, below the entrance of Backside Beck. 



These beds are the Middle Coldwell Beds of the Lake District. 

 It is doubtful whether the Lower Coldwell Beds are developed at 

 Cautley. 



The Upper Coldwell Beds form, at any rate, part of the Mono- 

 graptus-nilssoni Zone. They contain other fossils, such as Gardiola, 

 but no important collection has been made from them. 



The Bannisdale Shales with Monograptus leintwardinensis 

 also contain numerous fossils other than graptolites, but I have 

 nothing to add to the lists given in the Geological Survey Memoir. 

 There is much work yet to be done in collecting fossils from all the 

 Lower Ludlow rocks of the district. 



One deposit of Silurian age may be noted, although its exact 

 horizon has not been established. In Screes Gill, on the south- 

 western slopes of Yarlside, Mr. Middlebrook has found beds of gritty 

 white limestone, much contorted, but certainly many feet thick. 

 The fossils that have been obtained are poorly preserved and 

 do not indicate the horizon of the limestone, which is probably, 

 however, very low down in the Lower Ludlow succession. 



c. itelationship of the ashgillian beds to those of 

 other Areas. 



In the first place, it is evident that the Ashgillian Series is the 

 zone of Dicellograplus anceps. This fossil appears in the Phacops- 

 robertsi Beds and passes into the Stauroceplmlus Beds, being found 

 both above and below the contemporaneous volcanic rocks. ]S"o 

 graptolites have occurred in the Ashgill Shales. 



1 Q. J. G. S. toI. kvii (1911) p. 215. 



