168 Mr. Griffith, on the Order of Succession of the Older 



shire; and lam led to conclude, that the whole of the transi- 

 tion slate of the south of Ireland is high in the series generally, 

 and that the principal part belongs to the Silurian system. 



Our next point for consideration with regard to the di- 

 strict of Kerry, south of Castlemaine Bay, will be to deter- 

 mine where, in the graduating series between the chloritic 

 quartz rocks and the decided red conglomerate, we should 

 draw the line separating the Silurian system from the old 

 red sandstone. If we again refer to Dingle peninsula, we 

 find that the summit of Cahirconree mountain, together with 

 many other mountains of the district, is composed of rocks be- 

 longing to the old red sandstone, which rest iinconformahly on 

 the dark gray clay slate above-mentioned, and on the other 

 schistose rocks which succeed it. From this unconformability, 

 it would appear that the series of the schistose strata is not 

 complete in the peninsula of Dingle, and that it wants the 

 upper members which do occur to the south of Castlemaine 

 Bay. If we examine the old red sandstone series as exhibited 

 in the Dingle district, we find that the under beds consist of 

 rather fine-grained, red quartzose sandstone, for a thickness 

 varying from 100 to 150 feet in different localities; the sand- 

 stone is succeeded by thick beds of coarse conglomerate al- 

 ternating with coarse red slate, and these in continuation by 

 alternations of red and brown quartzose sandstone and coarse 

 red slate. 



Now if we compare the red strata which rest conformably 

 on the schistose rocks on the summits of the Reeks, the Purple 

 mountains, &c. we find red granular quartz rock in thin beds 

 underlying the conglomerates ; and considering these beds, 

 as in the Dingle peninsula, to represent the lower portion of 

 the old red series, I have drawn the line where the red quartz 

 rock terminates, and where a change is indicated by an alter- 

 ation in the colour of the rock, which becomes light reddish 

 gray, and the strata present a schistose, instead of a perfectly 

 granular structure. 



As a further proof of my opinion of the inaccuracy of 

 Mr. Hamilton's views respecting the order of succession of 

 the strata of the Killarney district, I shall now very shortly 

 describe the succession of rocks visible at the surface on the 

 north and south sides of the great fault where it traverses the 

 strata at Glena and Brickeen Island on the lower lake of Kil- 

 larney, which fault, as already mentioned, extends in a south- 

 eastern direction from the Gap of Dunloe, by the localities 

 in question, to the northern base of Turk mountain, &c. If 

 we trace the line of the fault on the shore of the lake imme- 

 diately to the north of Glena Banqueting House, and also 



