248 G. L. Elles 8^ E. M. R. Wood— On the Drygill Shales. 



Fhacops {Acmte) appendiculatus. 

 Thacops, species. 

 Lingula ovata. 



throughout the beds ; the following were found only in the south 

 fork of the gill, and the highest part of Drygill proper : — 



Trinucleus seticornis. 

 Trinucleus concentricus . 

 Trinucleics, sp. (allied to affinis). 

 jPhacops {Fterygometoptis) alifrons. 



Calymene cambrensis and Ortliis testudinaria do occur here, but are 

 far more common in the lower part of the gill. 



From the above lists it will be seen that the beds of the south 

 fork, and of the upper part of Drygill, are characterized by the 

 abundance of Trinucleus, while in the beds of the lower part of the 

 gill species of Ampyx, Stygina Miirchisonia, and Orthis testudinaria 

 are very abundant. 



It is obvious, therefore, that we have here two distinct faunas 

 represented, and we would suggest that the beds in the south fork 

 and upper part of Drygill belong definitely to a somewhat higher 

 horizon than the beds exposed elsewhere in the stream. 



Age of Drygill Shales. — Professor Nicholson and Mr, Marr (loc. 

 cit.) suggested that there was a resemblance between the Drygill 

 Shales and Dufton Shales, but considered that the abundance of such 

 fossils as Orthis testudinaria, Leptcena sericea, Calymene cambrensis, 

 Ampyx rostratus, and Stygina Murchisonice pointed to the beds being 

 at about the horizon of tbe Llandeilo Limestone. 



They originally considered that the beds were younger than the 

 Skiddaw Slates and older than the Coniston Limestone, but in a 

 more recent paper (Geol. Mag. 1891i) Mr. Marr expressed his 

 belief that this correlation was erroneous, and that the Drygill 

 Shales were probably more closely allied to the Coniston Limestone. 



In the light of further palasontological evidence, we would 

 emphatically confirm this suggestion. We believe that the beds lie 

 above the Borrowdale Volcanic Series, and we are convinced that 



