134 Dr. Bergf.r on the Geological Features 



§ 1. On the Geological Features of the North of Ireland, 



The arrangement adopted in the following observations is, that 

 suggested by the geological position and relations of the rocks 

 described. 



f: 



A. Granite. 

 I B. Gneiss and mica slate. 

 I. Primitive Rocks. c. Primitive limestone. 



< 



A, Granite, 



D. Primitive trap. 



E. Porphyry. 



F. Syenite. 



In the Mourne mountains and adjoining districts an extensive 

 formation of granite occurs, but neither here nor elsewhere in the 

 north of Ireland can we recognize the same varieties of that rock 

 which the mountains of Wicklow present. 



The granite now to be described seems rather to agree in its cha- 

 racters with the newer granite of the Wernerians, a rock sup- 

 posed to be closely allied to syenite. It appears to constitute almost 

 the whole mass of the Mourne mountains, whence it passes across 

 Carlingford-bay into the county of Louth, extending to the summit 

 of the Ravensdale mountains. It soon crosses the limits of Louth 

 to enter into Armagh, composing part of the Faughel hills, whence 

 it expands itself into a flat and elongated ridge, well known under 

 the name of Slieve Gulien, forming likewise the Slieve Girkin 

 or Newry mountains, and the lower and upper Fathom hills, of 

 which the latter keep close to the right bank of the Newry river. 



On the north-west side of the Mourne mountains, where they 



