664 



ME. E. E. COWPEE EEED OX THE 



[Nov. 1900, 



easterly dip of 60° to 70°. The fragments of black slate are 

 here more numerous than those of pink felsite. Between these 

 felsites and the extensive exposure of contorted black slates on 

 this strand occurs a mass of brecciated greyish felsite, in a soft 

 crumbling or greasy matrix of the same nature containing small chips 

 of the black slate. This mass, which is exposed all the way up the 

 face of the cliff, may represent an old pipe. 



The relations of the black slates to the intrusive greenish felsite 

 in the middle of Kilfarrasy Strand have been described and figured 

 on a previous occasion. 1 This greenish felsite is full of pieces of 

 the black slates, and the cliffs consist of it for some 50 yards west 

 as far as the faulted-in mass of Tramore Limestones {op. cit. fig. 11, 

 p. 734). Beyond this mass the intrusive nature of the felsites into 

 the slates after they had received their cleavage is very evident ; 

 and the irregular tongues and veins of felsite in the main mass of 

 Tramore Limestone are of the same petrological character, and belong 

 probably to the same group of intrusions. The different characters 

 of these Kilfarrasy felsites make it appear probable that they- do 

 not belong to exactly the same vent or group of vents, or perhaps 

 not to the same period, as those containing the numerous pink felsitie 

 fragments previously described. They have suffered also much more 

 from crushing and faulting. 



Passing now to the western side of Kilfarrasy Island, greenish 

 felsites of the same character without any discernible bedding 

 are found, penetrated by a sheet of beautifully columnar pinkish 

 felsite. A great sheet of diabase, subsequently described (p. 673), 

 also pierces them together with the greenish felsite and tuffs 

 with pink xenoliths, which again set in and continue westward 



as far as Annestown. 



Fig. 0. — Base of cliff letween Kilfarrasy 

 Island and Annestown. 



There is evidence also 

 of a slightly later 

 felsitie eruption in the 

 shape of an irregular 

 sheet of banded green- 

 ish felsite, which cuts 

 across the other acid 

 rocks, but is earlier 

 than the diabase and 

 has brecciated mar- 

 gins. At one spot 

 which suggests a 

 vent, there is a mass 

 of breccia of this 

 rock enwrapped and 

 almost enclosed by 

 felsite of the same 

 character ; some of the blocks in this breccia measure 4 feet in 

 length (fig. 6). At another neighbouring point there is also an 

 indication of the site of one of the vents of the earlier pink and 

 1 Quart. Journ. Geol. Soc. vol. lv (1899) p. 734 & fig. 10. 



A = Greenish banded felsite. 



B = Mass of coarse breccia of the same felsite. 



C = Vein of grey trachyte penetrating A & B. 



