386 PROCEEDINGS OP THE GEOioGicAL sociExr. June 18, 



Silurian ground beyond Thomastown, cuts directly across the strike 

 of the Old Red Sandstone, which rises from beneath the Limestone at 

 that place, and then winds, in a deep and picturesque ravine with 

 steep banks, between hills of slate and granite from 600 to 800 feet 

 high. It receives the influence of the tide at Inistiogue, in the heart 

 of these hills, and, passing through them, falls into the Barrow above 

 New Ross, and flows with it into Waterford Harbour. The Suir *, on 

 the other hand, flows constantly over low limestone ground to the 

 foot of the Knockmealdon Mountains, which deflect it into the lime- 

 stone valley of Clonmel ; so that it only cuts across the rising beds of 

 the Old Red Sandstone into the contorted Silurian rocks close to the 

 town of Waterford itself, where those rocks seem to have formed 

 originaUy lower ground than in other parts of their range. It has, 

 however, immediately after leaving the limestone, steep banks of 250 

 feet on each side of it. 



In the case of each of these rivers, if the gorges by which they 

 enter the Lower Palaeozoic country were now to be blocked up to the 

 level of the adjacent hills, or even to a height of only 800 or 350 

 feet above the level of the rivers, their pent-up waters would not flow 

 over the dams so formed, but would be poured into the Shannon, 

 either to the north of the Slieve Bloom, or out to Limerick along 

 the line of the railway ; or, if those passages were blocked up, they 

 would escape down the basin of the LifFey or the Boyne. This is 

 proof that these gorges were not excavated by the rivers since the 

 limestone ground attained its present low level, at all events. 



The origin of these gorges, as of that of the Shannon at ICilla- 

 loe, had been for a long time inexplicable to me. I think, however, 

 that I have found traces of an explanation in the district that I 

 shall now proceed to describe. 



3. The Biver Blackwater. — I have already mentioned the narrow 

 limestone vaUey that runs across Ireland, from Dungarvan to Dingle 

 Bay, which is for the greater part of its course drained by the River 

 Blackwatert. (See Map, PI. XIX.) 



* Spenser, in his poetical description of the British rivers, in the ' Faery Queen,* 

 after speaking of these three rivers as tliree brothers, 



^ •' Which that great gyant Blomius begot 



Of the faire nymph Eheusa. . ." 

 alluding probably to traditional tales now forgotten, thus proceeds to describe 

 them : — 



*' The first, the gentle Shure, that, making way 

 By sweet Clonmell, adornes rich Waterford ; 

 The next the stubborn Neure, whose waters gray 

 By faire Kilkenny and Rosse ponte boord ; 

 The third the goodly Barow, which doth hoord 

 Great heaps of salmons in his deepe bosome : 



All which, long sundered, doe at last accord 

 To ioyne in one ere to the sea they come ; 

 So, flowing all from one, all one at last become." 



Faery Queene, B. iv. cap. xi. stanza xliii. 

 The " great heaps of salmons " have, I fear, become almost as scarce in the 

 ^Barrow since the days of Elizabeth, as the "gyants" were previously to that period, 

 t It will be recollected that there are several other Blackwater Rivers in Ire- 

 land—one, for instance, which falls into the Boyne. 



