Kin ah an — On Granite and Metamorphic Rocks. 249 



Similar remarks are applicable to the Slieve-Croob granite, Co. 

 Down. 



In the Ordovicians there are numerous dykes of whinstone, 

 euryte, and felstone, which are cut off by the intrude of Mourne 

 mountain granite. These must, therefore, belong either to the 

 Silurian or Devonian periods, if that granite is of Carboniferous 

 age ; but if it belongs to the Triassic, then some at least of those 

 dykes may be Carboniferous. 



Carboniferous and Permian. — The Mourne Mountain 

 granite and elvan may possibly be of Carboniferous or of Permian 

 age ; but it appears to me more probable that they were intruded 

 in Triassic times. There are, however, intrudes and dykes of 

 whinstone, euryte, and felstone, which are older, and evidently 

 either Carboniferous or Permian. 



Sw^Riassio. — The granites and elvans of the Mourne Mountain 

 ^ict, and their associated felstones, eurytes, and whinstones, as 

 just stated, are supposed by me to be Triassic. South-westward of 

 Carlingford Lough are the Barnavave, or Mount Fathom elvan and 

 the Slieve Foze granitoid rock, with their associated whinstones, 

 eurytes, and felstones, all being post- Carboniferous, while they 

 seem to be pre-Tertiary, and were probably intruded during the 

 Triassic age. 



Tertiary. — In the Carlingford district are dykes and other 

 intrudes newer than the Slieve Foze granitoid rock, and all other 

 rocks in the district, while some of them are apparently identical 

 with the Tertiary rocks of Antrim. These rocks seem to have 

 their granitic roots in the country westward of the Lough, and also 

 in the great course of nevadyte coming up through the Newry 

 granite {Slieve Croub) in the vicinity of Goragh Wood, Bessbrook, &c. 



[Prof. Sollas has Litely suggested that these are the remains of a very recent volcano 

 in this district, the details of which he is working out at the present time.] 



Territorial Description. 



In some of the counties included in this territory no metamor- 

 phic nor exotic rocks are known to exist ; those in which most are 

 found are the counties Down, Louth, and Armagh, especially in 

 the neighbourhood of Carlingford Lough. 



SCIEN. PKOC. K.D.S. VOL. VI., FT. IV. fj 



