244 



GRANITES OF CARLINGFORD AND NEWRY. 



diameter, which is also circular, and lies to the south of Carlingford 

 Bay ; and third, the district of Newry, which extends from Slieve 

 Crook, on the north-east, for twenty-eight miles south-west, to Fork 

 Hill and Jonesborough, with an average breadth of six miles. In the 

 Mourne mountains the granite is fine-grained, and abounds in cavities 

 filled with crystals of the minerals which form the granite. This 

 rock consists of quartz, orthoclase, albite, and green mica. The 

 quartz is of a smoky-brown colour, and occurs in hexagonal crystals 

 in the cavities of the rock. The orthoclase is opaque white. The 

 albite occurs in the interstices of the orthoclase and quartz, the 

 mica is dark green and nearly opaque, and contains an unusually 

 large percentage of iron. Among the accidental minerals are 

 beryl, chrysoberyl, octahedral fluor spar, topaz, and peridote. 

 This granite somewhat resembles the elvans of Cornwall. The 

 mineral composition is stated at quartz 28, orthoclase 44*2, albite 

 27-8. 



In the Carlingford district there are two varieties of granite which 

 pass into each other ; and the summit of the Carlingford mountains 

 is formed of syenite, which passes into the granite in one locality, 

 and also passes into hornblende rock. In this district there are 

 numerous greenstones. According to Dr. Haughton, one variety of 

 granite which has the grains of medium size consists of quartz, 

 felspar, and green mica. The second variety, which is very fine- 

 grained, consists of quartz, white felspar, and hornblende. Although 

 different mineralogically, these granites are very similar chemically ; 



1 Haughton, Q. J. G. S., vol. xii. pp. 196-199. 



