472 Mr. Weaver on the Structure of the South of Ireland, 



tive transition series, and to all, or some, of such beds as the 

 case may be, when thus coloured, affixing also the term " old 

 red sandstone;" e.g., in Macgillicuddy's Reeks, in Dunloe 

 Gap, in Purple, Tomies, and Glenaa mountains, in Brickeen 

 island and Muckruss peninsula, and in the valley of Ken- 

 mare. Yet Mr. Griffith himself, in combating the positions 

 of Mr. Charles W. Hamilton, insists that the red sandstone, 

 where occurring in these localities, has been deposited con- 

 formahly on the older slate (which latter he seems disposed to 

 refer to the Cambrian or Silurian aeras), and in a descending 

 order graduates imperceptibly into that rock*. This being 

 admitted, v/hy not designate this a transition red sandstone 

 (as I have always done) in contradistinction to the old red 

 sandstone of the carboniferous epoch, found in unconformable 

 position, and commonly distinguished, in some parts of its 

 extent at least, by beds of red clay, red marly clay, and red 

 slaty clay ; e. g., in the Slieve Meesh range and in Kerry 

 Head? Much ambiguity would be avoided by observing this 

 difference in language. Again, after such an admission, it 

 may be asked, why are these rocks, together with the lime- 

 stone of Muckruss, of the islands of the Lower Lake of Kil- 

 larney, and extending toward that town, blended by Mr. 

 Griffith with the carboniferous series? This limestone within 

 its own area not only alternates with certain beds of the 

 older stratified rocks, the prevailing dip being to the south, 

 but in their lateral extension it is enveloped by and interlocked 

 with them, which latter relation is clearly proved by the posi- 

 tion cf the grey wacke, sandstone, and slaty-rocks in the north- 

 western portion of Muckruss peninsula, intervening between 

 the limestone of the islands on the north and that of the 

 south-eastern portion of the peninsula. Mr. Griffith con- 

 ceives he has solved the question by the introduction of a 

 faidt ranging from Dunloe Gap through Purple, Tomies, 

 Glenaa, and the southern part of Brickfeen Island, and under 

 Turh Lake to the main land east, where it is confessedly not 

 visible, diluvial matter occupying the surface. This supposed 

 fault does not appear to rest on any proof of actual disrup- 

 tion by an up or do\s:n throii\ or by a lateral movement, but to 

 be merely an inference drawn from the difference of strike 

 observable between the strata that have been interrupted in 

 their eastern and western continuation by the excavation of 

 Dunloe Gap or by the formation of Turk Lake or the Lower 

 Lake. I have seen no such dislocation in the masses extend- 

 ing from Dunloe Gap through Purple, Tomies and Glenaa 



* L. & E. Phil. Mag. March, p. 163, 166. 



