684 PROCEEDIlfGS OP THE GEOLOGICAL SOCIETY. 



6thly. We coiild find no trace of either fault or anticlinal ; and the 

 structure of the country, together with the palaeontological evidence, 

 is diametrically opposed to this hypothesis, the interposition or in- 

 terpolation of the great Middle group of slates and limestones with 

 tJieir definite fauna being fatal to this hypothesis; it cannot be 

 accounted for either on the ground of the fault or anticlinal, yet 

 must be if it be even allowed. This series in North Devon possesses 

 13 genera peculiar to it, and not known in any higher group. 



Tthly. I conceive it to have been an error to compare the Bri- 

 tish Devonian with the Irish types in the Carboniferous Slate, where 

 only one-third of the species are known to exist, the fauna of 

 that area either being derived from the typical Devonshire, or being 

 a remnant of the same that once existed there. The lower part of 

 the Irish Old Eed Sandstone, the base of which has nowhere been 

 seen, may not impossibly represent in time the Middle and Lower 

 Devonian (Middle and Lower Old Eed Sandstone) of North Devon, 

 where beds of red sandstone of no inconsiderable thickness (void 

 of life) exist, both at the base of the Middle or Ilfracombe beds 

 (Hangman grits) and the base of the Lower or Lynton slates (Fore- 

 land sandstones &c.). 



8thly. The true Old Eed Sandstone, as a whole, in one or other of 

 its three members (neither of which contains marine fossils), may be 

 the conformable base to the great Carboniferous series in some or 

 many areas ; but that it is so to the exclusion of the marine group 

 called the Devonian can only be believed by admitting that the 

 two series were synchronously deposited over every known area where 

 they both occur. This hypothesis would perhaps answer for very 

 widely separated geographical areas, where one or the other rested 

 upon the Old Eed Sandstone as its base, or where either the one or 

 the other was not represented either in time geologically, or space 

 chronologically ; but we can scarcely receive and apply that doctrine 

 to an area (our own) where the base of the Carboniferous itself rests 

 conformably upon the Upper Devonian series, acknowledged to be the 

 marine representative of the Upper Old Eed Sandstone of our own 

 and other areas, itself resting (as in Ireland and North Devon) 

 upon the non-fossiliferous Upper Old Eed. Such views cannot be 

 applied to any geographical area of so limited an extent as that 

 now occupied by the two groups (the Carboniferous and Devonian) 

 in the British Islands, the zoological differences being so great in 

 one and all, where they occur and are tested on biological grounds. 

 The doctrine of synchrony and difference of nature of sea-bottom 

 must be stretched to the utmost to establish a province or provinces 

 of organic remains within a few miles of each other, and that late- 

 rally, that would account for differences of such magnitude as those 

 which exist in the physical conditions and the fauna of the two 

 united systems. 



In Britain and Ireland alone, and chiefly in the very area we are 

 discussing, there are 383 species of Devonian fossils (as compared with 

 1748 species of Carboniferous) ; and of these 383, only oQ are com- 

 mon to the two systems {vide Tables II., IX., X., XI.) ; and this ratio 



