1 22 The Rev. W. C o n y b e a re on the 



\st System. The Mourn e Mountahis. 



The Mourne Mountains form a well defined group extending 

 from Dundrum bay to Carlingford bay in the southern extremity 

 of Down. 



Slieve Donard is the highest summit of this group ; it has beea 

 said to rise 3150 feet above the level of the sea, but the estimate 

 of Wr. Templeton,* who assigns only 2590 as the elevation of the 

 highest points of the Mourne Mountains, appears more correct, and 

 nearly agrees with that of Dr. Berger, who calculates its height at 

 2654 feet. 



To the west of the main group the Fathom hills, Slieve Girkin 

 or the Newry Mountains, and Slieve Gullen, all situated in the 

 south-east of Armagh, and the Ravensdale and Carlingford Moun- 

 tains in the north of Lowth, may be considered as its appendages. 



Granite is the prevailing constituent of all these ranges. 



To the north of the Mourne Mountains Slieve Croob composed 

 of syenite, and Slieve Anisky of hornblende rock, both situated in 

 the county of Down and barony of Lower Iveagh, constitute an. 

 elevated tract dependent upon but placed at some distance from the 

 main group. 



Hornblende rock and primitive greenstone are abundant on the 

 skirts of the granitic district. Mica slate has been noticed only in 

 one instance. Exterior chains of transition rocks advance far to 

 the west and north of this primitive tract, extending westwards 

 across Monaghan into Cavan and on the north-east to the southern 

 cape of Belfast Lough and the peninsula of Ardes. 



The primitive nucleus bears but a very small proportion in 

 superficial extent to these exterior chains, which are principally 

 occupied by greywacke and greywacke slate. 



* Mem. R. I. Academy, toI. 8. 



