167 



V. — Post Glacial Dknudation. 



In the same papers many facts were brought forward to shew 

 that the amount of denudation accomplished in post glacial times 

 is in many respects strikingly small. The insignificant quantity of 

 material deposited by the action of streams in our lakes of glacial 

 origin ; the very limited vertical erosion of the river channels ; the 

 presence, in very many instances, of glacial strias at the foot of, or 

 even on the faces of, some of the precipitous scars of the north ; 

 the generally-unweathered condition of large areas of moutonneed 

 rock ; the well defined form of the eskers, and of the moraines ; the 

 small quantity of weathered material strewing the slopes below very 

 many of the rock features of the north — all seem to point to the 

 conclusion that the close of the glacial period was very much 

 nearer to our own times than we have been, as a rule, accustomed 

 to regard it. Measuring the effects of post glacial erosion by the 

 known rates of erosion now in action, and making due allowance 

 for the fact that the low lying rock surfaces at the close of the 

 Glacial Period consisted of sound and unweathered rock, it seems 

 to me that a period of 20,000 years since the close of that period 

 is amply sufficient to account for all the denudation that can be 

 demonstrated to have been accomplished in Post Glacial times. 





G. AND T. COWARD, PRINTERS, CARLISLE. 



