ETH.ERIDGE DEVONIAN EOCKS AND FOSSILS. 687 



anticlinal along the line delineated by Professor Jukes can account 

 for the total absence of the Lynton and Ilfracombe groups to the 

 south of the Pickwell-Down range, which area is now occupied by 

 the well-defined Upper Devonian series m situ upon it. 



No fault can account for the absolute contrast that exists between 

 the fossiliferous sandy grits and slates that are in position on the 

 south side of Pickwell, and the barren glossy slates of Mortehoe 

 &c. that underlie the red grits and sandstones of Pickwell Down 

 at Potters Hill, and also the still thicker slates and associated con- 

 tinuous bands of organic limestones of Ilfracombe and Combe Martin, 

 which strike continuously on to Croydon Hill, in West Somerset ; 

 these ought to be accounted for (although they are not) by such hypo- 

 theses, as for thirty miles they strike and hold their place and 

 position without inversion, although disturbed by extensive undu- 

 lations. 



On zoological grounds the evidence is equally strong and conclusive. 

 No single coral out of the nineteen species in this area is known out 

 of this Middle group in higher beds ; and only ten out of the twenty- 

 five species of Brachiopoda pass up to the Upper Devonian strata 

 south of Pickwell, and four to the Carboniferous : whether these facts 

 have any parallel in the South-west of Ireland or not, they are 

 yielded by the structure and condition of North Devon. There is 

 yet another thick group of sandstones underlying the Ilfracombe 

 and West-Somerset Middle slates and limestones — the Hangman 

 Grits, from 1800 to 2000 feet thick ; they have no equivalent what- 

 ever to the south of the Upper Old Red Sandstones, and certainly 

 are not the Pickwell group repeated, with the Middle series troughed 

 in through undulation. These ought also to be accounted for to the 

 south of the supposed fault. Again, if the Lower or Lynton beds 

 are the same (or upon the same general horizon) as those of Paggy, 

 Marwood, and Croyde &c. &c., to the south, no system of faults 

 can account for or do away with the well-marked intermediate po- 

 sition of the Middle Devonian group ; and no anticlinal situated 

 so far to the south of the great mass of the country- as Pickwell 

 could divide the series without accounting for the Carboniferous 

 series of Yenn, Swinbridge, &c., which should become evident to 

 the north at Lynton, or trough in between, which they do not. 



Professor Jukes, again, in his paper, " Notes for Comparison 

 between the Rocks of the South-west of Ireland and those of Devon," 

 &c. &c., pp. 10 and 11, would infer, or lead those to believe who 

 had not seen the country, that the roUed or undulating beds along 

 the north coast, at Morte Bay &c., are confined to the lowest groups, 

 which, he says, are " probably the Morte Slates and beds below 

 them." These quartzose Morte slates are not the lowest, they are 

 the highest of the Middle group, and overlie the fossiliferous Ilfra- 

 combe series proper, and hold their place all across North Devon 

 into West Somerset. The whole of the fossiliferous slates and 

 limestones of Ilfracombe and Lynton are below these and the red 

 sandstones of Pickwell ; neither will the rolling therein mentioned 

 do away with the fossil evidence tending to disprove that " the 



