Kinahan — 0)1 Irish Arenaceous Rocks. 565 



[Ordovician) there are quartzytes and quartz rock (gneissen), while 

 in the less altered portions to the north and to the westward (the 

 latter classed as Laurentians) there are grits. 



To the east of the county, in the mountain groups (Slieve 

 Anghta), there are also Ordovician rocks; they are not, however, 

 metamorphosed. To the north of the county, from the Atlantic 

 eastward to Loughs Mask and Corrib, is a long tract of Silurian , 

 while margining the Slieve Aughta Ordovicians, and in two places 

 on the shores of Lough Corrib — at Oughterard and Cong — are 

 Carboniferous sandstones. In the Calp, north-east of Athenry, are 

 calcareo-argillaceous sandstones. 



Cambrian (?), Arenig, and Ordovician. — In general the 

 quartzyte and quartz rock are splintery, or break irregularly ; in 

 no case are they fit for dressed work. As much better stone can 

 easily be procured, they are rarely used, except for local rough 

 work. Some of the grits in the less altered Ordovicians are fair 

 stones. 



Silurian. — Good stones from fine to coarse conglomerates. 

 Yellowish-greens, browns, and reds ; some easily worked, but not 

 in use, as the localities are backward, and there is no demand. 

 Have only been used in local works. When building Maam 

 bridge, although there was excellent and suitable sandstone in the 

 vicinity, Nimmo brought limestone by water from Cong, Co. 

 Mayo, as he considered it cheaper. 



Carboniferous. — Some of the stones are well suited for cut- 

 stone purposes. Those at the mearing of the county, to the west 

 of Mount Shannon, have been already mentioned (Co. Clare, p. 

 539). To the east of the county are other good stones, locally 

 used in Woodford and Portumna. 



A little south of Cappagh, and north of Featherstone Lodge, 

 westward of Woodford, there are stones capable of being ground 

 to a smooth surface, and of making flagging similar to the " Kin- 

 nity flags," King's County (p. 576). 



Benmore. Two miles from Woodford. — A fine freestone ; can 

 be raised in large blocks ; suitable for all cut-stone purposes. 



Slieve Dart. North of Dunmore, to the north of the county, 

 and partly in the Co. Mayo. — The massive pebbly grits were 

 formerly extensively wrought into millstones. In this hill, not 

 yerj long ago, was raised very extensively a very thin laminated 



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