140 , ON A BOULDEE OF HORNBLENDE PICRITE. 



dence (supposing no physical difficulties presented themselves) the 

 Pen-y-Carnisiog boulder to have been derived from that parent rock. 

 This would afford us most valuable evidence as to the direction in 

 which the agent of transport (doubtless ice) had formerly moved. 

 The south side of the Lleyn peninsula, even if the rocks corresponded 

 (which they do not), seems excluded by physical considerations ; 

 but I may remark that, though I have examined many boulders in 

 Anglesey, I have failed as yet to identify any of them with rocks 

 from the Lake District or from Scotland, and think that we must 

 look to the mountains of North Wales for the home of those which 

 cannot be found in Anglesey itself. 



