400 Dr. Wheelton Hind — Lower Culm of North Devon. 



Radiolarian rocks also are found in the Pendleside series. There 

 is, therefore, a very remarkable and close resemblance in the faunas 

 of the Coddon Hill Beds of the Lower Culm and the Pendleside 

 series : so practically identical, indeed, are they, that there can be 

 little or no doubt that they ai'e the homotaxial equivalents of 

 each other. 



The Venn, or Posiclonomya Becheri Limestone. 



The fauna contained in the black limestones of North Devon is 

 not so rich in species as that of the Coddon Hill Beds, but the 

 following species are abundant : — 



Posidonoini/a Becheri. Ghjphioceras striatum. 



Pseudamusiumjihrillosum. ,, sphcericnm. 



Ghjphioceras spirale. Orthoceras cijlindraceum. 



,, crenistria. 



Plant Remains : Cordaites, sp. 

 Posidonomya Becheri. — I only recognise one species. The examina- 

 tion of a large number of specimens has convinced me that the forma 

 P. tnberculata and P. lateralis are accidental, due to conditions of 

 preservation and degree of flattening by compression. 



I regard P. Becheri as an important zonal form, indicating a horizon 

 somewhat above that of P. compressus. I have found this zone 

 constant in position from Old Head of Kinsale in the south of Ireland 

 to Clavier and Vise in Belgium. The zone has no great vertical 

 depth, and I am unable to indicate the precise thickness, but in the 

 Midlands, beds characterised bj^ G. spirale extend some hundreds of 

 feet above P. Becheri. 



I have, as in the case of ProJecanites compressus. found specimens 

 of P. Becheri at a lower horizon. It occurs in the Yoredale series of 

 Wensleydale above the Great Scar Limestone, and I have found it 

 actually in the top beds of the Carboniferous Limestone at Castleton, 

 but in these places it has, with it, a typically Carboniferous Lime- 

 stone fauna. 



At Poolvash, Isle of Man, P. Becheri occurs in black limestone 

 and shales, which succeed the shelly white upper beds of the 

 Carboniferous Limestone. With it is the following fauna : — 



Solenomya costeUata. Ghjpliioeeras crenistria., and a crushed 



Orthoceras Morrisianum. Ceplialopod which Mr. Crick identifies 



,, sulcatiun. as Stroboceras sulcatum. 



I have not been able to get at the beds at the base of the series, 

 where I should expect to iitid Prolecanites compressus and Trilobites. 

 Some curious beds containing P. Becheri occur at Budle, North- 

 umberland, the real horizon of which is very doubtful and vague. 



Ireland. 

 In CO. Dublin the Pendleside series succeeds the Carboniferous 

 Limestone near Sherries ; at the former horizon P. Becheri is found 

 in abundance. At Old Head of Kinsale, south-west of Cork, 

 P. Becheri occurs in hard shaly beds in a curious sequence of 

 shales and thin indurated calcareous beds. In South-West Cork, 

 as in Devonshire, the Carboniferous Limestone is absent, and there is 



