Kinahan — On Irish Arenaceous Rocks. 611 



farther west in Knockmeeldown, one group appears to graduate 

 into the other; the Yellow Sandstone margining the Devonian. 

 The Yellow Sandstones also occur in places eastward (estuary of 

 the Suir), and in a band to the northward of the Ordovicians. 



In the south division of the county, that is south of the valley 

 from Dungarvan to the Blackwater at Lismore, there are, east and 

 west, ridges of sandstones, separated by troughs of Carboniferous 

 limestones or shales ; and in these ridges, as in Cork, farther west, 

 if there is a sufficient thickness of strata exposed, the Yellow Sand- 

 stone {Lower Carboniferous Sandstone) is found to graduate down- 

 ward into the Devonian. 



In the Bonmahon mining district, in two or three places, very 

 small patches of red or purplish conglomerate and sandstone have 

 been found lying on, or partly in, the Ordovician. These must be 

 either of Silurian or Devonian age, probably the latter : that is, 

 small outliers of the Comeragh conglomerates. 



Ordovician. — The major portion of the grits and sandstones 

 are not fitted for general cut-stone purposes, although some dress 

 on the bedded surfaces ; nor are they in much repute for common 

 walling purposes, the associated slate being preferred, except in a 

 few cases. There are, however, some green tuffose sandstones that 

 are associated with the Exotic bedded rocks ; these do not seem to 

 have been much utilized in this county, although very similar 

 rocks have been used during ancient and modern times, in the 

 Co. Wexford, where they have produced good and durable 

 work. 



Grange Hill. Waterford. — Here there is a slaty grit that has 

 been much used. It is very strong and hard, but very difficult to 

 raise, on account of the absence of back joints ; it dresses well on 

 the face, but not on the edges. It was used in the ancient round 

 castle, called Reginald's Tower, which shows the durability of the 

 stone. The dressed work round the opening in this structure is 

 of Carboniferous Sandstone, which has weathered much more, but 

 evenly, than the Grange Hill stone. 



Devonian and Carboniferous. — In the Co. Cork, the Silu- 

 rians and Devonians are intimately connected, and hard to separate. 

 They were, therefore, grouped together. In this county, however, 

 it is not the beds below the Devonians but those above them that 

 are intimately connected. It therefore is expedient here to group 



SCIEN. 1'KOC. K.D.S. — VOL. V., PT. VII. 2 T 



