TRANSACTIONS OP THE SECTIONS. 83 



thickness of any formation, founded solely on the persistence of the 

 dip of the strata towards any particular point. 



To the south of Lismore a low ridge intervenes between the valleys 

 of the river Blackwater and the river Bride at Tallow. This ridge is 

 composed of coarse red slate, and occasionally rather fine-grained 

 greenish gray clay slate. The strata for the most part dip to the 

 south, but in the centre of the ridge they form an anticlinal axis. 

 Approaching the valley of the Bride at Tallow, we again meet with 

 yellowish white sandstone beds containing Calamites similar to those of 

 the valley of the Blackwater, and also greenish gray imperfect slate, 

 which, as before, is succeeded by the limestone ; here the calcareous 

 strata form a regular trough, those on the north side dipping to the 

 south, and on the south side to the north, beyond which we have the 

 usual succession of strata which are interposed between the red schistose 

 beds and the limestone. 



Proceeding to the southward, the section crosses the barony of 

 Barrymore in the county of Cork, which forms the base of the lime- 

 stone trough of the valley of Middleton and Youghal, and thence con- 

 tinues to its southern termination at Cork Head. Within this space 

 a succession of strata similar to that already described, is repeated 

 three times ; first we have the red quartzose slate ridge of the barony 

 of Barrymore, succeeded by the limestone trough of the valley of Mid- 

 dleton and Youghal ; next the low red quartzose ridge of Great Island 

 in the harbour of Cork, succeeded by the limestone of that harbour, 

 Carrigaline, &c. ; and Ifistly, the red quartzose ridge of Hoddersfield, 

 which is succeeded on the south side by the blackish gray carboni- 

 ferous slate which forms so characteristic a feature along the south 

 coast of the county of Cork. This blackish gray slate appears to be 

 similar to the greenish gray slate of the valleys of the Suir, the Black- 

 water, and the Bride ; it underlies the limestone of the valleys of Mid- 

 dleton and of Cork Harbour, where it contains small Orthocerata in great 

 abundance, and in some localities it contains Calamites. Approaching 

 the limestone of Cork Harbour at Rosslillan, Renniskeddy, &c. the 

 slate assumes a gray colour, is interstratified with limestone, and con- 

 tains numerous fossils belonging to the carboniferous series, identical 

 with those which occur in a similar position at Killinamack, in the 

 county of Waterford, close to Knocklofty Bridge, over the river Suir. 

 On the evidence of the sections thus briefly described, Mr. Grifiith 

 grounds his conclusion, that the limestones of the valley of the Bride, 

 Cork Harbour, &c. belong to the same geological series as those of the 

 Blackwater and the Suir, which are connected with the great car- 

 boniferous limestone field of Ireland, and this inference from the ob- 

 served position of the rocks is stated to be confirmed by the evidence 

 at present collected from organic remains. 



In respect to the section of the strata near the western coast of the 

 counties of Kerry and Cork, already mentioned, which was also exhi- 

 bited by Mr. Griffith, similar proofs respecting the order of super- 

 position of the strata were brought forward to show that the limestone 

 of Killarney, Kenmare, and Bantry belongs to the carboniferous, and 



g2 



