610 Scientific Proceedings, Royal Dublin Society. 



"over-bearing" of drift, or useless rocks, that overlie them; they 

 are, however, inferior to the Calp Sandstone, and no quarry in 

 them seems now to he worked. 



Edenclorlc. Two miles northward from Dungannon. — Reddish ; 

 fine-grained ; slightly micaceous ; soft ; not now worked. 



Sand and Gravel. — Eskers extend from Killymoon, near 

 Cookstown, to Dungannon, and thence by Ballygawly, Clogher, 

 and Fivemiletown into the county of Fermanagh ; in them there is 

 an unlimited supply of good pit sand and gravel. Some of these 

 so-called Eskers, as in the Pomeroy valley, are evidently Glacial 

 river gravel. (See Monaghan, p. 592.) Good pit sand can also 

 be procured near Gtortin. River sand occurs in the Eoyle, at 

 Lifford Bridge, near Strabane ; in the Moyne, near Omagh, and 

 elsewhere ; near Castlederg, and in many of the rivers and streams 

 from the hills. 



WATEKFOItD. 



Occupying a considerable area in the east of the county is a 

 large tract of Ordovicians. Overlying this, to the west, in the 

 Monavullagh and Comeragh Mountains, are massive conglomerates, 

 sandstones, and slates, which to me seem to be littoral accumula- 

 tions of the "West Cork and Kerry Devonians. 1 If this suggestion 

 is correct, portion of the younger rocks, in the Graltees, to the 

 northwest, and Slievenaman to the north, ought to be also Devo- 

 nians. These Devonians, as in Cork and Kerry, seem to graduate 

 upward without any quick or decided change, into the Yellow 

 Sandstone or Loiver Carboniferous Sandstone; as in general the 

 dips in both groups of rocks are similiar. This, however, is 

 not always so, as in the neighbourhood of Crlenpatrick, to the 

 southward of Clonmel and Kilshelan, there is a sudden change in 

 the direction of the dips, the later rocks dipping northward at low 

 angles, and the older southward at high ones. This change may 

 possibly only be due to a line of fault ; but it may be caused by 

 an unconf ormability : it should, however, be more carefully ex- 

 amined into. However, to the southward in these hills, and also 



1 John Kelly, I think, "vyas of a similar opinion, hut I do not know exactly where 

 he stated it. 



