of the North of Ireland, 151 



The conglomerate contains in great abundance large pebbles of 

 quartz, and more rarely of hornstone porphyry ; also of a rock 

 wliich appears to have been a greenstone porphyry, but is much 

 altered by decay ; and lastly of mica slate. The coarsely granular 

 variety consists of quartzose concretions imbedded in an argillo- 

 calcareous cement. 



This sandstone formation appears to rest on the mica slate 

 which succeeds it on the north side of Cushendon bay, and occu- 

 pies the district of Cushleak described in a former article. At the 

 opposite or N.W. extremity of that district we may again trace the 

 sandstone in Murloch bay : it there appears very distinctly on the 

 beach near the great Whin dyke, in its conglomerate form. 



To the westward of Church bay in the Isle of Rathlin, and near 

 a spot called the Black rock, I found fragments of the old sandstone 

 associated with blocks of syenite in such abundance as to impress 

 me with a strong belief of the former existence of both these rocks 



of Loagh Strangfovd v, ith its cap of greenstone presents so obvious an analogy to the 

 structure of Cragnashoack at the southern extremity of the floetz trap chain in London- 

 derry, that we might be almost tempted to infer the identity of the sandstone in 

 both instances, and, since that of Cragnashoack is certainly the newer variety, to 

 question the propriety of assigning to that of Scabro hill the antiquity which has been 

 claimed for it in the text : its apparent connection with the sandstone of Belfast lough, 

 also seems to favor the idea of its belonging to the newer variety, for in travelling between 

 Belfast and Newtown Ards, the road is said not to exhibit any rock but sandstone, in situ, 

 although hills of greywacke rise within a small distance on either side : yet the fact 

 mentioned by Dr. Berger of the alternation of this sandstone with greywacke, seems 

 decisive as to its age. 



The sandstone of Cushendon also appears to require further examination : one of the 

 most interesting facts concerning it appears to have escaped Dr. Berger's notice, namely, 

 its connection with a formation of reddish clay porphyry. The observations made by 

 Mr. Buckland and myself on this formation will be found in the account of the sections 

 presented by the coast, appended to these extracts. It is only mentioned at present as 

 ^€ording an analogy between the sandstone which skirts the mica slate of Cushleak, and 

 occurs in a similar situation in the island of Arran. 



