142 Dr. Berger on the Geological Features 



bed of primitive limestone, before mentioned. It has there a ten- 

 dency to hornblende rock, while in Bennady-glen it displays a 

 granular texture and a few plates of mica. 



2. Greenstone, 



I have found greenstone in Ravensdale park, at the foot of the 

 mountain of that name, and on the west side of the Faughel hills. 

 I suspect that in those two instances, the latter particularly, it forms 

 beds in the newest granite. 



3. Greenstone slate 



rests against the acclivities of the Mourne mountain, but the strata 

 never rise very high, seldom exceeding 5 or 600 feet ; one instance 

 only was observed of a hill exclusively formed of this rock, and 

 that did not attain a greater elevation than about 800 feet. 



Attempts have been made to quarry it for roofing slate, and 

 were the works conducted with spirit they might perhaps supply 

 Ireland with as good slate as that now imported from Wales, which 

 appears to belong to the same formation. 



The greenstone slate of the Mourne mountains contains ap- 

 parently no crystallized hornblende in the basis, though it is dis- 

 seminated through the latter, as is shewn by the manner in which 

 k fuses before the blowpipe. I have remarked in it some crystals 



