Vol. 56.] THE IGNEOUS ROCKS OF COUNTY WATERFORD. 663 



Sheep Island. — Greenish felsites of the same general type, and 

 containing small xenoliths of pink felsite and black slate, continue 

 westward to the small strand near Sheep Island, where a vent is 

 situated on a projecting point, about 200 yards east of the spot 

 marked ' Boatstrand ' on the 6-inch Ordnance-Survey map. The 

 eastern side of the vent is formed by the greenish felsite, with a boss 

 of grey horny felsite rising up into it. The agglomerate filling the 

 vent consists of fragments of greyish felsite, some measuring 2 

 or 3 feet in diameter, and cemented together by a pale greenish- 

 yellow matrix. A green felsite resembling this matrix is intimately 

 associated with this agglomerate, having been extruded into it and 

 around it. 



The whole headland running out to Sheep Island is extremely 

 complicated, and exhibits a group of closely-packed vents with felsites, 

 tuffs, and agglomerates. A green felsite enclosing large fragments 

 of black slates, and betraying evident signs of considerable crushing, 

 is exposed at the waterfall. This is faulted against a non-xenolithic 

 pink felsite ; and the western side of the extreme point of the head- 

 land shows a section where the pink felsite is seen in contact with a 

 coarse dark-greenish ash or agglomerate, crowded with fragments 

 of a similar pink felsite. The line of contact is nearly vertical, and 

 along it the ash is bedded, but probably this pseudo-stratification is 

 due to pressure. A stack of similar ash occurs on the foreshore, 

 with fragments of a more reddish felsite in it. The agglomerate at 

 one point near the base of the cliff consists almost entirely of 

 huge blocks of a pink felsite, and a largo mass of black slate is also 

 a conspicuous object in the middle of it. It appears that reddish 

 and pink felsites were first extruded and consolidated, before the 

 violent explosion took place which shattered them and filled the pipe 

 with their remains. The pink felsite was then injected into the 

 agglomerate. The green tuff passes laterally into less coarse and 

 better compacted tuffs, associated with a special type of felsite 

 crowded with xenoliths, which extends almost uninterruptedly to 

 Annestown Bay. 



A fragment of the reddish felsitic outflow is preserved in a needle- 

 like stack close by on the foreshore, and its character corresponds 

 to that of the fragments in the green tuff. 



A later phase of volcanic' activity is represented here by a pipe 

 filled with a slightly compacted breccia of greyish felsite, associated 

 with the solid grey felsite breaking through the green tuffs and 

 xenolithic felsites. The latter gradually lose most of their xenoliths 

 as we follow them westward, and some of the associated flows, 

 resembling them macroscopically and microscopically, are quite free 

 from any inclusions. Sporadic patches of very coarsely xenolithic 

 rock occur, perhaps pointing to subsidiary vents or to an intermittent 

 violence in the eruptions. 



Kilfarrasy. — Yet farther west, at the point called the Black 

 Door, by Kilfarrasy Strand, the greenish xenolithic felsites are still 

 met with, and show a rude kind of bedding with a south-south- 



