I90 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Irish Coomhola "beds, with Anodonta and Palceopteris or Adiantites, 

 being undoubtedly of Upper Devonian or Upper Old Red Sandstone 

 age. Mr. Kinahan would class the Old Eed Sandstone of the 

 Dingle and Cork area as Lower Carboniferous, and corresponding 

 in the Limerick area to the Lower Carboniferous sandstones and 

 shales. Kinahan further states that in no place in Ireland has 

 the Old Eed Sandstone a defined upper boundary, one group gra- 

 duating into the other. Furthermore, he says, only in Munster 

 and in the hills between Lough Erne and Pomeroy, in the counties of 

 Fermanagh and Tyrone, is the Old Eed Sandstone at the absolute 

 base of the Carboniferous formation, as in all other places the 

 rocks so called and described are on different geological horizons, 

 ranging up to the base of the Coal-measures *. 



As far back as 1863 Jukes and Salter stated that the yellow lime- 

 stone of the South of Ireland is the upper part of the Old Eed Sand- 

 stone, with the Coomhola grits between it and the Carboniferous 

 slate with Avicula damnoniensis and Cucullcea &c. 



Pisces. — 50 genera and 125 species of fish range through the 

 Old Eed Sandstone. It can hardly be said that ichthyic life com- 

 menced prior to the commencement of the deposition of Old Eed Sand- 

 stone or the Devonian age. The few genera and species that made 

 their appearance in the British seas at the close of the Silurian 

 period (8 genera and 12 species, 10 of which passed to the Old Eed 

 Sandstone) can only be traced into the very lowest beds of the Old 

 Eed in the Silurian area of Ludlow, Kington, and Ledbury, and 

 scarcely passing beyond the passage group ; we know them not 

 higher in the system. In the North of Scotland and in the Orkneys, 

 Caithness, and Cromarty area, the Lower Old Eed Sandstone is 

 known to have furnished 18 genera and about 60 species ; no prior 

 stratigraphical relation or origin is known. They occur in that 

 region, like the strata or rocks which contain them, fully developed 

 and in vast numbers. Unlike the Old Eed Sandstone of the Silu- 

 rian area the formation has there no f ossiliferous base. The Silurian 

 rocks are absent, the sandstones and conglomerates lying uncon- 

 formably upon the metamorphic rocks. The only other organisms 

 are Phyllopod and Eurypterid Crustacea, with remains of 10 or 11 

 genera of plants. 



To no living geologist are we so much indebted for our intimate 

 knowledge of the Old Eed of Scotland as to Prof. A. Geikie. His 

 paper in the 4 Quarterly Journal of the Geological Society 'f, on the 

 Old Eed Sandstone of the South of Scotland, and his last elaborate 

 essay upon the Old Eed Sandstone of Western Europe J, are ex- 

 haustive so far as they have gone. Prof. Geikie shows that there 

 is no middle Old Eed Sandstone in either North or South Scotland, 



* Vide Kinahan, ' Geology of Ireland/ pp. 50-94, for his views and much 

 valuable information. 



t " On the Old Red Sandstone of the South of Scotland." By A. Geikie, Esq. , 

 F.G.S. Quart. Journ. Geol. Soc. vol. xvi. pp. 312-323. 



t " The Old Eed Sandstone of Western Europe." By A. Geikie, LL.D., 

 F.R.S. Trans. Roy. Soc. Edinburgh, vol. xxviii. 1878. 



