Kinahan — On Irish Arenaceous Rocks. 581 



reous. They are purplish, reddish, and greenish in colour. Where 

 fine-grained they cut easily and well, but are not durable. A 

 green variety, raised out of an adjoining quarry, was extensively 

 used in the building for the new railway station at Limerick. 



An agglomerate, that rises in massive, squarish long blocks, 

 was used in the ancient megalithic structures in the neighbourhood 

 of Lough Grur. 



In general the Coal-measure grits are very quartzose, and hard 

 to cut or dress, and are not favourably thought of. They have, 

 however, been used in many of the bridges. In places there are 

 excellent flags, similar to those imported from Money Point, Co. 

 Clare. These have, to some extent, been worked in the neigh- 

 bourhood of Athea, and also at Barna ; and the latter were used 

 in Newcastle and Rathkeale. When first raised, they are soft 

 and easily tooled, but afterwards they become very hard. They 

 also occur in the hills near Grim. 



Sand and (travel. — Pit sand occurs in the neighbourhood of 

 Limerick, near Kilmallock, near Eathkeale, and in other places. 

 Good river sand can be procured from the Shannon above Lime- 

 rick, in the Deel river, near Newcastle, and in greater or less 

 quantities in the mountain streams. Shell sand for manure was 

 formerly procured from the estuary of the Shannon. There are 

 also in places, at about the 240 feet contour line, accumulations of 

 gravel suitable for road purposes. 



LONDONDERRY. 



The sandstones occur in the Ordovician, Llandovery ■(?), Silurian, 

 Carboniferous, Triassic, and Jurassic groups. To the south of the 

 county, coming in from the Co. Tyrone, are older rocks, probably 

 the equivalents of the Arenig or Cambrian, that are metamorphosed 

 into gneiss and schists. 



Ordovicians and Llandovery (?) . — These are more or less 

 metamorphosed. Some of the less altered sandstones cut fairly 

 well, but are not in request, as better stone can be procured in the 

 Carboniferous. A peculiar, finely-laminated sandstone {book or leaf 

 sandstone) ; is very good for walling purposes, and has been exten- 

 sively used in the neighbourhood of Derry. 



Prehen (Derry). — Bluish; of a slaty nature. Does not stand 



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