THE LAKE-BASINS OF IARCONNAUGHT. 119 



rains, when the supply exceeds the drainage by soak- 

 age. There is, however, an exception, when one of 

 these bars forms across the mouth of a corry, a place 

 in which they are not uncommon, for reasons mentioned 

 hereafter, while describing the formation of corrys 

 and their lake-basins. 



Other meteoric bars may be due to landslips, as 

 during dry weather cracks will form in mountain 

 slopes, whether the drift be meteoric or glacial. If 

 such cracks run up and down the incline, or perpen- 

 dicular to the trend of the valley, they only form 

 channels afterwards to be occupied by streams ; but 

 if they are transverse that is, rudely parallel to the 

 lower part of the valley water, after rain, will collect 

 in them, and finding no egress, will eventually force 

 out large masses, that slide down to the bottom of the 

 valley and dam up the drainage. Hooker has de- 

 scribed such debacles in the Himalayas which are of 

 considerable magnitude ; but none of those remarked 

 in West Gralway are very large. 



Other bars that have been noted may possibly be 

 due to avalanches during the time that snow and ice 

 existed in the hills, as we know that at the present 

 day, in Alpine regions, avalanches occur in special 

 places, and by their frequent sliding, accumulate bars 

 of drift. In other places, lakes may possibly be 

 formed by beavers' dams. This suggestion, however, 

 is merely conjectural, and prompted by the form of 



