240 



Scientific Proceedings, Royal Dublin Society. 



IRON ORE IN VEINS. 



[The mode of occurrence of some of the ores in this list is not as true veins ; yet at the 

 same time they are not in true heels. Like the ores of the Eocene and Coal 

 Measures, they are apparently of a secondary formation, a part of a bed or 

 beds becoming ferriferous, the ore being found in an irregular " bunch" or "shoot " 

 that underlies with the stratification of tbe associaied rocks. This is espe- 

 cially the case with some of the ores in the Ordovician rocks which have been de- 

 scribed as " beds of ore." The localities of some of the ancient iron mines are now 

 quite unknown, while the exact sites of others are uncertain. In the latter cases 

 the places in the neighbourhood of which the mines were probably situated will 

 be mentioned. The localities are arranged in counties.] 



