Mr. Weaver on the Geological Relations of the South of Ireland. 15 



and iron, giving rise to extended exudations, which spread over the face of the cliffs in dirty brown 

 yellow, and white streaks. It rarely occurs, however, in the red conglomerate and red sandstone. 

 These are more especially distinguished by the diffusion of the red and yellow oxides of iron, which 

 substances frequently occupy their interstices. 



(18.) Numerous veins of quartz are found in all the rocks of the transition series on this coast, 

 and of calcareous spar in most of them. They are, however, least frequent in the red conglo- 

 merate and red sandstone. Veins of hornstone also often traverse several of the rocks, in some 

 places pursuing a very tortuous course. All these veins vary from a thread to four, six, or eight 

 inches in width, and rarely exceed a breadth of one or two feet, frequently ramifying, and termi- 

 nating in filaments. Many of them are wholly barren and discontinuous ; but others, whether 

 consisting simply of quartz, or of calcareous spar, or a compound of both, bear copper and lead 

 ores, either separately or conjointly ; those bearing copper ores separately being the most common. 

 Where these ores occur, the face of the cliffs is generally stained with blue and green streaks, ari- 

 sing from the decomposition of the sulphurets of copper. 



(19.) In one portion of this district I met with organic remains, namely, 

 immediately eastward of the Bonmahon river, both upon the coast and inland, 

 disposed in fine-grained greywacke and grey wacke slate. In the former quarter 

 they appear in the face of a cliff, which consists of coarse slate, the cleavage 

 planes of which are nearly vertical ; but the organic remains form a number 

 of parallel lines, arranged in an horizontal position, thus traversing the fissile 

 structure of the rock, and constituting so many layers, at the distance of three 

 to six inches apart, a disposition which might give rise to some curious specula- 

 tion. This deposit occupies a considerable portion of the face of the cliff 

 upward, though in length it extends only about twelve fathoms. I must remark, 

 however, that the organic remains are not wholly confined to these parallel 

 lines, occurring also scattered through the mass of the rock. They here consist 

 of three or four species of Polyparia, several bivalves, and a Turbo ; but inland 

 I found, in addition to these, the Asaphus caudatus, and the whole may bear 

 a strict comparison with similar remains in Kerry, Gloucestershire, &:c., /ii/- 

 sterolites, or the casts of bivalves, also appearing among the number, and 

 closely resembling those figured by Messrs. Phillips and Woods as occurring 

 at the summit of Snowdon ^ 



(20.) Generally speaking, this transition series is connected, on the north, by 

 insensible gradations with the great body of clay-slate which prevails in that 

 part of the county of Waterford, the whole sustaining, upon the higher lands, 

 unconformably, extended overlying masses and caps of the old red sandstone^, 



' Annals of Philosophy : December 1822. 



- The horizontal position of the old red sandstone formation in the Monavoullagh range is well 

 marked in a drawing representing the precipice in that formation, which overhangs the Lake of 

 Coumshenane 1100 feet in height. (See Dublin Penny Journal of Oct. 20, 1832.) 



