M'Heniiy — Report on the Ox Mountain Rocks. 



375 



Subsequent to the intrusion of the basic rock, and prior to the 

 first acid one, a certain amount of movement in the rock-masses took 

 place, as is shown by the sheared and banded condition of the 

 inclusions of the earlier rock in the acid granulites (fig. 3). A 

 still later intrusion of granitic material took place, the masses and 

 veins of which only occasionally show signs of deformation from 

 ■earth-stresses (fig. 4). 



Eegarding the probable age of the two earlier intrusions of basic 

 and acid materials, they are at least pre-Old Red Sandstone, as the 



Fig. 4<. 



20 FEET 



Early basic igneous rock (B.) and later acid granulites (C.) invading the sedi- 

 mentary limestone zone, all three groups having been subsequently sheared 

 together, and later uncrushed granite vein (G.). 



Five miles E. of Clifden, Connemara. 



massive conglomerates of this latter formation are largely composed of 

 the detritus of all the varieties of igneous rocks and the associated 

 sediments into which they intrude. Besides, they are seen to rest 

 truly unconformably on them at many places. Therefore, if it be 

 acknowledged that the altered sedimentary rocks are of Ordovician 

 and early Silurian age, it is most likely that the period of this igneous 

 complex belongs to early Devonian time. In my opinion they are the 



