Ktnahan — On Irish Metal Mining. 289 



on account of the depression in the iron trade. In the Ordovician 

 rocks the iron in general, is associated with manganese. 



Traces of copper and sulphur ores have been found in the rocks 

 {Ordovicians) of the Ballynascreen mountains, but none of the veins 

 have been opened up. 



Prior to 1641 Boate records gold as occurring in the gravels of 

 the Moyola river, but since then none seems to have been found. 



There is a possibility that Coal Measures, with profitable coals 

 may yet be found under the Trias at the south-east of the county. — 

 See Ulster Coal-field, Co. Tyrone, p. 298. 



Portlock calls attention to large beds of ochre at Aughlish and 

 Tamnagh, in the parish of Banagher, and Grlenviggan in the 

 parish of Ballinascreen, as suitable for making red paint, similar 

 to that employed in Sweden to paint and preserve the wooden 

 houses. The surface deposits, or bog-iron-ore, is in places at 

 present exported, to be used in the purification of gas. 



Longford. 



In the north-east of the county, coming in from the Co. Cavan, 

 is the margin of a tract of Ordovician rocks. The rest of the area 

 is principally Carboniferous Limestones, with, to the north, a margin 

 of Carboniferous Sandstones and Shales. In a few places are small 

 protrudes of Ordovicians, associated with Carboniferous Sandstones. 



The localities for minerals are few (see Lists) ; the most im- 

 portant are the iron lodes at Cleenragh and Enaghan, near Lough 

 Growna. These were worked in the seventeenth century, and also 

 prior to 1870, by Dr. Eitchie of Belfast. In the earlier times 

 they seem to have been smelted in the county, but Eitchie ex- 

 ported them, carrying them across the lake in boats, and thence 

 by rail to the port. Silver-lead is recorded as occurring in the 

 Carboniferous Limestones at Longford. 



Louth. 



The major portion of this area is occupied by Ordovician rocks, 

 on which, to the south, west, north, and north-east, are small 

 tracts of Carboniferous Limestones, with its Sandstones and Shales. 



8CIEN. PROC. K.D.S.VOL. V. PT. IV. X 



