176 NATURAL SCIENCE [September 1898 



points to their river-like ramifications. In the valleys containing 

 these asar, detached patches of sand are sometimes found — the 

 wreck, he believes, of a great deposit of sand. In such a deposit, 

 rivers would soon cut down a deep channel. In the bottom of this 

 channel pebbles and gravel would collect, then gravel, or sand, or 

 mud layers. In time, the course of the river is diverted, the 

 adjacent sands wear rapidly away, and the more compacted deposits 

 of the river-bed longer resist denuding influences, and in the end 

 stand out in bold relief as asar or eskers. 



One can hardly forbear exclaiming — Too clever by half ! The 

 author uses, to the full, the romancist's privileges. He has every- 

 thing he requires at hand and in abundance, and what he no 

 longer requires he gets rid of with the readiness of a necromancer. 

 Rivers have, no doubt, often struck out new lines of action for 

 themselves. But here everything makes its bow and retires just 

 when it has acted its part. 



Thomas Fitzpateick. 



St Ignatius' College, 

 Galway. 



{To he continued.) 



