256 DR. H. HICKS ON THE MOETE SLATES, AND [May 1 896, 



History) ; Mr. F. Cowper Beed, of Cambridge ; Mr. J. Hopkinson, 

 and Prof. C. Lap worth. 1 



1 [A complete resume of the literature of the North Devon rocks up to the 

 year 1867 has been given by Mr. Etheridge in his paper already referred to. 

 Up to the year 1868 the views put forward by Sedgwick, Murchison, Godwin- 

 Austen, De la Beche, and Phillips received general acceptance, but during that 

 and subsequent years Prof. Jukes suggested modifications which tended towards 

 a very different interpretation. In his paper in the Quart. Journ. Geol. Soc. in 

 1866, vol. xxii., he says at p. 321 : ' As I shall have to maintain that all the first 

 geologists of the day, including Prof. Sedgwick, Sir R. I. Murchison, Mr. Weaver, 

 Sir H. De la Beche, and Prof. Phillips, have misunderstood the structure of the 

 country, let me hasten to avow my belief that nobody whose observations were 

 confined to Devon and Somerset could have arrived at any other than their con- 

 clusions. I fully admit that the rocks near Lynton appear to be the lowest, and 

 that there appears to be a regular ascending succession of rock-groups from 

 Lynton to the latitude of Barnstaple. I am, however, compelled to dispute the 

 reality of this apparent order of succession, and to suppose that there is either a 

 concealed anticlinal with an inversion to the north, or, what I believe to be 

 much more probable, a concealed fault running nearly east and west through 

 the centre of North Devon, with a large downthrow to the north, and that the 

 Lynton beds are on the same general horizon as those of Baggy Point and 

 Marwood.' 



In 1867 Mr. Townshend M. Hall, whose researches have added so much to our 

 knowledge of the North Devon rocks and their fossil contents (Quart. Journ. 

 Geol. Soc. vol. xxiii. p. 371), subdivides the North Devon series, in ascending 

 order, as follows: — Foreland group, Lynton zone, Martinhoe beds, Ilfracombe 

 group, Morthoe group, Cucullcea-zone, Pilton beds — and says : ' From the Fore- 

 land on the north to Barnstaple on the south the rocks have an almost uniform 

 dip to the south, usually at a high angle, presenting to all appearance an 

 unbroken succession.' 



Mr. Etheridge, in his paper of the same year {op. cit, vol. xxiii. p. 568), 

 strongly controverts the views put forward by Prof. Jukes, and maintains that 

 the succession in North Devon is one unbroken and continuous series. He 

 subdivides the rocks in ascending order as follows (p. 580) : — 



Lower f a. Lynton Sandstone. (Foreland Beds.) 

 Devonian. 1 b. Lynton Slate 3. 



M'ddl \ c ' Hangman Grits. 

 Ti ^ninn 1 ^" Calcareous Slates (fossiliferous). (Ilfracombe Beds.) 

 devonian, y ^ Qr ^ unfossillferous slateSj ( Morte gl a tes.) 



(f. Pickwell Down Sandstones. 

 -r-r- .„ I g. Baggy and Marwood Slates, etc. 



Devonian < k Cro ^ don W™^} Beds. 

 Devonian. ( { Braunton Beds 



^ k. Pilton and Barnstaple Beds. 



He further says at p. 694 : • After very careful investigation into the physical 

 structure of North Devon, as well as a critical examination of the organic 

 remains contained in its diversified rock-masses, I can come to no other 

 conclusion than that the series of sandstones, slates, and limestones ranging 

 from the Foreland and Lynton on the north to Pilton and Barnstaple on the 

 south are one great and well-defined system, and equally well divisible into 

 three groups, a Lower, Middle, and Upper Devonian series, each equally well 

 characterized by a fauna, the zoological facies of which are sufficiently distinct 

 to determine them one from the other.' 



The following appears to be the final arrangement suggested by Prof. Jukes ; 

 it occurs in a paper read before the Royal Geological Society of Ireland in 



