478 



Proceedings of the Royal Irish Academy. 



the overlying ones of the ''Lower Old E,ed Sandstone" type, and 

 therefore to be confirmatory of the inima facie presumption afforded 

 by their fossils that the rocks of the Pomeroy series are of Cambro- 

 Silurian age. 



LiSBEIlA-W PoSSrLIPEEGTJS EoCKS. 



Two groups occur to the northward of Lisbellaw, the later lying 

 unconformably on the older. 



^ Eed sandstone and sandy shales, with some " 



I green beds. At Lisbellaw there are mas- ,,^ r\ 



\ ■ 1 L. ■i.-u ■ ^• St '' Lower Old 



n sive conglomerates with mliers oi green , -d o 11 



2. <^ 1, 1 >n, • 1 ^ >±tED bANDSTONE ' 



j shales. The massive conglomerates ap- [ ,^.. • s 

 I pear to be very local, as they do not occur | ^ -'' 



to the north-eastward or westward. J 



I 



!Grey to dark blue shales, slates, and grits, \ 

 with, in some places, green grits ; some i 

 beds fossiliferous. They are occasionally v 

 metamorphosed in part as if by paroptetic \ 

 action. J 



Catmbeo- 



SlLTJElAN. 



The rocks of group 1 occupy only a small area, in which there are 

 few exposures ; they are fossiliferous near the hamlet called the Slate 

 Quarry. From the rocks seen and a knowledge of other Irish Cambro- 

 Silurians it is suggested that they are probably on a somewhat lower 

 geological horizon than the rocks of the Pomeroy series. Prom a 

 letter received from Mr. "W. Staunton, it would appear that this 

 authority, judging from the contained graptolites, considers the rocks 

 of the Pomeroy series to be the equivalent of the Lower Llandovery, 

 or the uppermost rocks of Cambro-Silurian age. 



