THE DEVONIAN ROCKS OF ILFRACOMBE. 85 
the whole of the part of Devonshire in which the “ Pilton Beds ” 
occur is coloured for “ Carboniferous Beds.” 
Thus Mr. Jukes regarded the Red Sandstones of the northern 
part of the Quantock Hills, those of Dunster, Minehead, and 
Porlock in Somersetshire as of Old Red Sandstone age. The over- 
lying slates of Lynton, Ilfracombe, &c., he identified with the Car¬ 
boniferous slates, while the sandstones of Pick well Down, Haddon 
Down, and Main Down he regarded as probably a repetition of Old 
Red Sandstone brought up by a concealed fault;* and he con¬ 
sidered the overlying slates of Marwood, Braunton, and Pilton 
as again repeating the Carboniferous slate, which passed gradually 
upwards into the Culm Measures.! 
On the other hand, Professor Hull, F.R.S., thinks that it is 
possible to draw a line which will cut off the beds in Devon that 
can be really compared to the Irish rocks, and yet leave certain 
sandstones to the Upper Devonian. The series of beds, according 
to his opinion, lie thus :— 
Upper Devonian.— Upcot (or Pilton) Flagstones. 
Pickwell Sandstones. 
Morthoe Slates. 
Middle Devonian.— Ilfracombe Beds. 
Hangman Grits. 
Lower Devonian.— Lynton Shales. 
*/ 
Foreland Grits.J 
With this last opinion Lyell and Geikie concur. They consider 
that all the rocks on the north side of the River Taw are true 
Devonian, and they classify them thus :— 
C.— Upper Devonian, or Pilton Group. 
Grey shales and calcareous beds, with yellow, brown, and red 
sandstones, about 8,000ft. thick. These contain various 
plant remains; the following Cephalopoda— Clymenia 
Sedywickii and C. plicata ; Goniatites multilobatus ; various 
Brachiopoda—Spiriferas and Rhynchonellas, and a Crus¬ 
tacean, Phacops iatifrons. 
* This fault no geologist has found. 
f Woodward, “ Geology of England and Wales,” p. 71. 
+ See Geikie’s “ Text Book of Geology,” p. 699 ; Ramsay’s “ Physical 
Geology,” p. 99; Jukes-Brown’s “ Historical Geology,” pp. 138-9. 
April, 1893. 
