284 Davies — On Glyn Ceiriog. 



As some of tlie features of this district (wliich Mr. Salter properly 

 suggests, are deserving the attention of Geologists), have already 

 had some attention paid them by myself, you will, perhaps, allow 

 me to say that, in 1859,^ I described the various beds of which this 

 hill is made up, noticing some of their peculiarities and rarer fossils. 

 In 1863, in a paper of mine on "The Bala Limestone of North 

 Wales and its associated beds,^ " I classed the Upper Limestone of 

 the hill as " Himant Limestone," as Mr. Salter now proposes. 



In a section which accompanied that paper, I represented the over- 

 lying schists " Pale shales very fossiliferous," as I called them (the 

 No. of Mr. Salter's letter) as conformable to the underlying beds. 

 In a letter which I afterwards received from Professor Sedgwick, 

 that gentleman — the value of whose labours iri North Wales I esti- 

 mate very highly— said, " the order of superposition is quite clear, 

 yet there is, I believe, a hreak in the order of succession f and he 

 adds I should be grateful to you for more information respecting the 

 group of "pale shales very fossiliferous." These remarks led me 

 to review the matter, and the result was that I found the " pale 

 shales of the Pentre hill and round about, to be unconformable to the 

 Bala group below, as Mr. Salter now wagers that, upon examination, 

 they will be found to be ; and if your readers will refer to the Geo- 

 logical Magazine for 1865, page 344:, they will find, in a section of 

 the beds referred to, that I have named the uppermost band of lime- 

 stone, " Hirnant Limestone ;" and that I have represented these pale 

 shales of the Pentre as unconformable to those below. 



Mr. Salter truly says, that working this district is like working a 

 museum ; and I may mention, in addition to the fossils he enumerates, 

 a beautiful one once examined and named by himself Ischadites tessel- 

 latus, which I quite expected to see in the excellent plates of fossils 

 that adorn Professor Eamsaj^'s admirable memoir on North Wales. 



Plenty yet remains to be done there, and I promise any geologists 

 who may be willing to hammer for a day or two about Mynyd Fron 

 Frys, a chaiining time of it. If gentlemen, who would like a joint 

 meeting for the purpose of more fully exploring the spot, will com- 

 municate with me, I shall be glad to make the necessary local ar- 

 rangements, and to join them on the occasion. 



I am, Sir, yours very truly, 



D. C. Davies. 



Coney-green House, Ostvestey, 

 Ma^ 3rd, 1867. 



FISH IN DEVONIAN EOCKS. 

 To the Editor of the Geological Magazine. 

 Sir, — Can you favour me with space for a few friendly remarks 

 on the P.S. of Mr. Salter's letter in your May number. 



The fish defence spines in my collection are two in number, — 

 one from Looe Island, and one from Looe ; not both " from the 



' Vide Proceedings of the Oswestry Field-club, pages 32-35. ^ i\)\([_^ page 71. 

 See also for section, Proceedings of the Liverpool Geological Society, 1863-4 ; for 

 list of fossils, ibid., 1864-5. 



