500 Proceedings of the Royal Irish Academy. 



NOTE ADDED IE THE PEESS. 



Prom Glashagli, the valley adjoining Lord Belmore's quany, Mr. 

 Thomas Plunkett, M E.I.A., has sent me a piece of a fossiliferous 

 boulder of a greenish argillaceons rock. This rock is very similar to 

 some of the rocks of the "Pomeroy series," and contains fossils com- 

 mon therein ; hut it is also similar to some of the green argillaceous 

 rocks of Tanderagee. In these, however, no fossils have been found 

 as yet. The principal fossil, Leptcena serica, is one of the character- 

 istic fossils of the Toormakeady Silurians, and therefore it may possi- 

 bly occur in the Tanderagee " grey and green beds." The boulder 

 could scarcely have come from the Pomeroy area, as the driftage from 

 that was towards the south ; but, as I have already suggested, there 

 may possibly be an outlying exposure of these rocks to the north of 

 this place ; while it is also possible that the " Glashagh fault" may 

 bring up the rocks of the "Pomeroy series" under the drift of the 

 valley. 



EXPLAJS^ATION OF PLATES. 



Plate XYI., Fig. 1. — Map of tlie Pomeroy area, showing the prohable extent 



of the rocks of the " Pomeroy series " and some of the 



eiiiptive rocks of the Altmore district. 

 ,, Fig. 2.— Aghafad section, showing the prohable imconfonnahility 



between the rocks of the " Pomeroy series " and the 



" Lower Old Red Sandstone." 

 ,, Fig. 3.- — Glenbeg section, showing the reversed position of the 



eurites and tuffs. 

 ,, Fig. 4. — Shane Bamagh's Sentry-box, section of the eurites, tuffs, 



and associated rocks. 

 ,, Fig. 5. — Sections showing the relations between the Silirrian rocks 



of Louisburgh, Creggaunbaun, Mweelrea, Salrock, and 



Lough Muck. 

 Plate XVII. — Longitudinal section indicating the original position of the rocks 



in the Silurian basin between Clare Island, Co. Mayo, 



and Cushendiin, Co. Antrim. The probable outline of 



the floor of the sea is indicated, while the faults that 



have since shifted it are left out. 

 , , Sections showing the relations between the beds in the Mweelrea 



and Partry Mountains with those to the north in Croagh 



Moyle. 

 ,, Three series of vertical sections : one showing the sections at the 



pi'incipal points in the main longitudinal sections ; 



another of the principal sections in the longitudinal 



section from Mweelrea to Croagh Moyle ; and the third, 



the sections along the cross sections from Culfin to 



Louisbui'gh (fig. 5, Plate XVI.) . 



