EIHEEIDGE DEYONIAX KOCKS AXD FOSSILS. 589 



higher divisions of which pass into the Carboniferous Slates of the 

 Barnstaple and Bideford area, &c. ; and in the traverses from Dunster 

 to Dulverton, in which the entire series of the rocks of West Somer- 

 set are passed over in the direct line of their dip or deposition, I 

 have been enabled to determine that the succession is complete. 

 From Timberscombe through Oaktrow to Ashwell, the lower red 

 sandstone and slates belong to the Lynton group, being immediately 

 and conformably succeeded at Cutcombe and AYheddon Cross by the 

 the grey gritty slates of the Ilfracombe series, the two divisions of 

 which, the Ilfracombe projDer and Mortehoe beds, occupy all the 

 country to the latitude of Oxgrove, being here and there (as on the 

 coast) in this distance rolled or undulated, but nowhere showing 

 any evidence of an extensive fault or inverted order. At Oxgrove, 

 as at Huish Champflower (Wiveliscombe) on the east, and ]y!orte- 

 hoe on the west, they unmistakeably pass under the superincum- 

 bent Upper Old Red Sandstone of Pickwell, Dulverton, and Main 

 Down &:c., without any visible fault, or any evidence of a deep- 

 seated one of sufficient magnitude to invert the order of the rock- 

 masses of the two areas (that is, the south and north). This so- 

 called (by Professor Jukes) " Old Eed Sandstone " is the base 

 of the upper division of the Devonian rocks, on which rest the 

 slates of Baggy, George Ham, Marwood, Sloly, High Bray, &c., 

 which constitute palaeontologically the Upper Devonian series, and 

 which are succeeded by the prohaUe equivalents of the Irish Coom- 

 hola beds at Croyde, Braunton, Barnstaple, &c., and so on into the 

 true Carboniferous series. Thus, in this, to me, highly typical in- 

 land succession, as contradistinguished from that seen on the coast, 

 where the whole series may be determined in situ and their masses 

 compared, we have no break or fault of any magnitude whatever, no 

 movement of the strata to any extent, certainly not sufficient to 

 cause inversion ; for the undulations of the slates near the base of the 

 thick red sandstones are such only as would occur in pelding and 

 softer beds during either sudden or long-continued movements, espe- 

 cially when overlain by some 3000 feet of massive, thick-bedded 

 sandstones, and along an extensive tract of country. The undula- 

 tions and local reversions of dip in the slates of the Middle Devo- 

 nian or Ilfracombe group are not of great magnitude throughout 

 their entire strike. Its base rests upon the second series of sand- 

 stones, or the Hangman and "Woodabay beds ; and at its summit 

 are the Pickwell and Dulverton Upper Old Red Sandstones, which 

 are unfossiliferous throughout. 



5. Valley of the Barle and ivest of Dulverton. — The valley which 

 the river Barle traverses, and the rocks through which it passes, 

 afford good sections of the '•' Old Red Sandstone." The country 

 from Dulverton to Mauncy Castle is occupied by the Pickweil- 

 Down (Dulverton) red grits and sandstones, which have reversed 

 dips and undulations corresponding to those described on the Exe 

 river, and on the roads east of Dulverton; but they are better 

 shown here, on account of the greater exposure of the rock-masses. 

 A little north of Dulverton, some 1500 feet of thick-bedded, highly 



