550 Scientific Proceedings, Royal Dublin Society. 



Errarooey. Near Crossroads. — Yellowish ; improves in colour on 

 exposure ; silieious ; durable ; free-working ; can be plugged, and 

 hammers well ; can be raised in long scantling, and is capable of 

 long bearings ; was used in the foundations and coping-stones of 

 Myra Bridge and in the Roman Catholic Church and School-house, 

 Crossroads. The vein extends eastward and westward. 



Minnagran. Seven miles from Grlenties. — Here the rocks are 

 very much altered, and appear to be more of a gneiss than a 

 quartzyte. The stone is used for dressed work, and in the vicinity 

 it is called "millstone." 



At Carrick, eight miles northward of Milford, and in places to 

 the westward, there is a reddish, porous quartzyte, that squares 

 fairly well, but will not cut. It is a good building stone, and 

 was largely used in the building of Manorvaughan, or Hulroy 

 House. It keeps its colour, and has a good effect. Locally it 

 is called " red granite." 



Kitty dug. North of the Letterkenny "Waterworks. — Quartzose- 

 sandstone ; rises in long massive flags ; capable of long bearings ; 

 good for rough building, such as lintel and posts in farm buildings. 



Carboniferous. — In the already mentioned Carboniferous, 

 outlier at Ballymastoker Bay, Fanad, there are red conglomerates 

 and sandstones. The first were formerly used, to a small extent, 

 to be wrought into flax-crushers, while the sandstones were used 

 for local purposes. 



In the parish of Muff, on the west of Lough Foyle, and to the 

 north of Derry, the rocks consist principally of reddish sandstones. 

 and conglomerates, which are used for local purposes. 



To the south-east of the county, margining the Co. Fermanagh,, 

 that is, northward of Pettigoe, there are in places stones of yellow- 

 ish-grey shades. At Lettercrann, about three miles from Pettigoe, 

 were procured the stones for the stations on the Enniskillen and 

 Bundoran Railway. 



In this tract some of the stones are specially suited for flax- 

 crushers and millstones, and forty or fifty years ago many were 

 made. 



In the Carboniferous rocks, near Donegal and Ballyshannon, 

 some of the sandstones are of good characters. They are from 

 pale cream- colour and nearly white to reddish and purplish ; from 

 very fine to coarse conglomerates. Formerly from this county 



