THE VALLEYS OF SOME OF THE IRISH LAKES. 151 



was very wet, and on the 21st the whole of the 

 plain was covered with water, over twenty feet 

 deep in places. The area under water, including 

 the flooded land about Coole Lough, was at least 

 500 acres ; but when we consider the extent of the 

 water-basin which drains into Coole Lough, it is not 

 surprising. 



Some of the lakes and turloughs on the low 

 ground are affected by the rise and fall of the tide, 

 the rising tide damming up the egress of the fresh 

 water, which accordingly rises in the lakes or tur- 

 loughs. This cannot be observed during floods, as 

 from the expanse of water the rise and fall would 

 only be a few inches, but during dry weather it is 

 most perceptible. This phenomenon can be very 

 well seen in the holes in the vicinity of the mine on 

 the west of Caherglassaun Lough, although six or 

 seven miles from the sea at Kinvarra. 



Lough Mask lies on the north of Lough Corrib, 

 and is in some respects similarly circumstanced, as 

 the rocks of the area occupied by its basin are in 

 part of carboniferous age and partly much older, the 

 latter being greatly broken up by faults and the like. 

 The lake-basin 1 has a bearing of about 1ST. 20 E., similar 

 to the general bearing of the main joints in the coun- 

 try on the east, while to the S.W. are two arms or 

 bays, branching from the main basin. The greatest 



1 Admiralty Chart, No. 2318, Ireland. ' 



