390 PROCEEDINaS OF THE GEOLOGICAL SOCIETY. [Juiie 18', 



5. The Eiver Bandon^. — The Old Eed Sandstone ridge which 

 forms the southern boundary of the Cork Valley extends right across 

 Ireland, from Knockadoon Head, inside Capel Island, to Sheep's Head, 

 between Bantry and Dunmanus Bays, It has a valley aU the way 

 along its southern side, part of which we have already described as 

 the Carrigaline and Cork Harbour Yalley. To the west of Carriga- 

 line, it is drained by a brook called the Owenboy Hiver, running into 

 Cork Harbour, but between Bandon and Dunmanway by the River 

 Bandon. There is a watershed in the vaUey, about TJpton, between 

 the Bandon basin and that of the Owenboy, the " lowest connecting 

 gap " of which is about 140 feet above the sea, the highest point in 

 the valley hereabouts being one of 180 feet. 



The River Bandon issues from the neighbourhood of Shehy Moun- 

 tain into the vaUey near Dunmanway at a level of 190 feet, and runs 

 along it a little north of east for 20 miles. It has a level of 54 feet 

 above the sea at the town of Bandon, but then cuts deeply into the 

 ridges on the souths and becomes tidal at Inishannon. Prom this 

 point the river winds in a deep and often precipitous ravine, with 

 banks rising to heights of 200 feet and more, across a succession of 

 ridges that reach to heights of more than 400 feet, until it works its 

 way out by a circuitous and surreptitious course into the south-west 

 corner of Kinsale Harbour. Here again we see that, if the ravine 

 at Inishannon were closed up to the level of the hills on each side of 

 it, which are there from 280 to 300 feet above the sea, the lake that 

 would then be formed would not be drained along the course of the 

 present river- valley ; for, long before the water could flow over the 

 dam in that direction, it must run over the watershed at Upton, 

 which is only about 140 feet high, and the River Bandon would then 

 follow the course of the Owenboy out to Carrigaline and Cork 

 Harbour. 



The case of the Bandon River is, however, by no means so striking 

 as those previously described ; and to the west of Dunmanway the 

 longitudinal valley becomes very irregular and sometimes ill-defined, 

 being broken up by subordinate ridges and transverse valleys, espe- 

 cially that of the River Hen, until we approach Dunmanus Bay, where 

 it again assumes its normal form of a straight longitudinal E. and "W". 

 valley. These irregularities are probably attributable to its having 

 the Carboniferous Slate instead of the more homogeneous Limestone 

 for its subjacent rock. 



Part III. EoRMATioN op the Teansveese Ravdtes. 



In seeking for the explanation of the mode of formation of the 

 valleys of the three rivers now described, it appears that the first 

 question to be answered is, How were these transverse ravines 

 formed which thus tap the valleys of the rivers far above their natural 

 mouths by bringing tidal canals into them, at right angles to their 



* " The pleasant Bandon, crown' d with many a wood, 

 The spreading Lee, that, like an island fayre, 

 Encloseth Corke with his divided flood." 



Spencer, jp'c^r^ Queene, 



