158 Archdeacon Verschoyle on the Geology of the North Coast of 



vails to Bangor. The hill of Addergool on Lough Conn, and Glen Nefin, 

 on the flanks of the Barnagee Mountains (a prolongation to the south-west of 

 the Ox Chain), are old red sandstone, in regular beds, though remarkably 

 coarse, being formed of rolled pebbles of unusual dimensions. The thick beds 

 of peat which generally cover the declivity of the mountains, preventing an 

 exact knowledge of the boundaries of the rocks, the demarkations can be 

 ascertained only in the ravines, where the streams have removed the bog, 

 soil, and decomposed strata. 



The Inferior or Primary Rocks. 

 E. Quartz Rock. 

 This formation overlies the gneiss in many places along the south declivity 

 of the Ox Mountains. It is generally composed of very fine, white, quartz 

 grains, firmly compacted, and free from extraneous mixture ; and it is laminar 

 or schistose in structure. This may be considered the purest variety, and of 

 such Nefin in Tyrawly, 2639 feet high, consists ; also the vertical beds in the 

 headlands, east and west of Broad Haven. In other places it is mingled with 

 white, compact felspar, the laminge being thicker and less regular ; and mica 

 also enters into the compound, which then graduates into gneiss. Rising 

 from below the old red sandstone, on the banks of the Owenmore, in Erris, 

 it prevails around Bangor and the south shore of Carromore Lake ; but on 

 the east bank mica slate appears. The northern part of the Mullet is also 

 quartz rock ; and in a perpendicular cliff, at a place called Mycreeny, between 

 Blind Harbour and Erris Head, are several very interesting and perplexing, 

 shifted quartz veins. (See the following gketch. No. 1.) 



