484 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 20, 



Spirifer TJrii (S. unguiculus). 



lineatus ? 



Verneuilii. 



Barumensis ? * 



disjunctus, including S.giganteus. 



" grandavus. 



bisulcatus. 



Atrypa desquamatat. 

 Rhynchonella pleurodon. 



subdentata. 



— — rhomboidea, 



pugnus ? 



Euomphalus serpens. 

 Natica nexicosta. 

 Pleurotomaria cancellata. 



antitorquata. 



■ aspera. 

 Loxonema sinuosa ? 



nexilis. 



tumida. 



Bellerophon (trilobatus?), probably B. 



bisulcatus, Eoem. 

 Orthoceras cinctum. 



laterale. 



striatulum. 



striatum, M l Coy. 



fusiforme. 



Cyrtoceras rusticum. 

 Nautilus megasipho. 

 Goniatites insignis. 

 — — bisulcatus. 



biferus. 



Clymenia laevigata. 



striata. 



linearis. 



fasciata. 



sagittalis. 



plurisepta. 



valida. 



Phacops (Calymene) granulatus. 



This list, it may be observed, differs in almost every point from 

 the Barnstaple list, and the Petherwin beds were probably deposited 

 in deeper water. It is trae that several of the characteristic fossils 

 are the same in both series ; but there is an entire absence in the 

 Pilton or Barnstaple series of the Clymenioe and Goniatites, so 

 characteristic of Upper Devonian strata on the Continent, and also 

 of the Phacops granulatus. I have taken the list as it stands in my 

 note-books, adding to it the species quoted by Professor Phillips, 

 for which we are chiefly indebted to the researches of Mr. Pattison. 

 Mr. Lee, of Caerleon, contributed some good materials. 



It will be seen, too, that this list fails in two or three important 

 points to tally with that of the fossils from the Barnstaple series. 

 Instead of the large Phacops latifrons, we have the small P. granu- 

 latus ; Spirifer Barumensis is, I believe, quite absent ; Productus 

 prazlongus is not found there; and Strophalosia subaculeata takes 

 the place, as an abundant species, which S. caperata occupies at 

 Barnstaple. Much of this change may be due to a different depth 

 of water for the deposit ; but it cannot be wholly so ; and I should 

 look for the equivalent of the Petherwin beds, which are exactly the 

 "Clymenien-Kalk" of the Prussian geologists, in the red slates of 

 Morte Bay. 



It was in vain to search for the Pilton group along the borders of 

 the Culm-measures, which, contrary to expectation, I found to be 

 unconformable to the Devonian beds, at least near Launceston. And 

 in its lowest beds, very black shales with much chert in them are 

 the usual state of things in the Culm-measures. 



The shales or slates in which the Devonian limestones of Pether- 

 win occur are very much like, in a general sense, those of Ilfracombe — 

 that is, pale grey slate, with no sandstone-beds, and bearing all the 

 marks of deep-sea accumulation. 



* I am not sure of this species. 



t This I think doubtful, but it is important to notice it. It may be Atrypa 

 reticularis. 



