100 THE RELATIONS BETWEEN FAULTS, OPEN JOINTS, 



occupied by the Barrow ; it can even be traced as far 

 as Arklow, but the eastern extension does not form 

 a conspicuous feature. Further south, from Dingle 

 .Bay to Dungarvan, is another valley, that of the 

 Blackwater, along which, as far east as Mallow, a 

 large fault is conspicuous. 



Between these systems there are others that run 

 in more or less parallel lines. In some these lines 

 have an easting from north, in others a westing, while 

 between these there may be other systems extending 

 more or less east and west. In a few places, especially 

 if the rocks are ancient or metamorphosed, such as to 

 the south-east (Wicklow and Wexford), to the north- 

 west (Gal way and Mayo, also in Donegal), and to 

 the north-east, there are limited tracts having 

 minor systems peculiar to themselves ; however, the 

 principal lines in the last named extend into the 

 south-west part of Scotland. The connection between 

 the joints, breaks, valleys, and lake-basins of West 

 Galway will be described hereafter in detail, as also 

 those of S.W. Cork, where, although the rocks are 

 not of very ancient date (Carboniferous), there 

 are special systems of master joints, breaks, and 

 faults. 



North of the fault (Blackwater valley fault) that 

 has been proved in the valley that extends from 

 Dingle Bay to Dungarvan Harbour, ten large faults, 

 or systems of faults, have been proved and traced, 



