172 



GEOLOGY OF ARBAN. 



this strength, and the vast labour which has been employed 

 in rendering it impregnable to the attacks of an enemy, it is 

 probable that it was used as an encampment by the early 

 islanders for the security of their families in the case of 

 invasion."* The local antiquarians point out the "hill of 

 council " adjoining, where the chief men met, in case of alarm 

 by beacon fires on the heights of Dippen or Dun-fion ; and tell 

 you that there was a larger population in old times than now 

 along these glens and sheltered slopes. On the brow of the 

 terrace over the waterfall there are several slabs of greenstone 

 marked with glacial striae, directed nearly east and west, that 

 is, in the direction down the glen. The hills westward are 

 all of overlying trap, and in some places shew veins of pitch- 

 stone. This terrace, the lowest of several ascending steps, 



sweeps round south-eastwards in a high cliff, and comes upon 

 the shore at Leargie-beg, where for more than a mile south- 

 wards it forms sheer precipices of highly prismatic rock resting 

 on sandstone (fig. 32), which it covers for a long way with its 



* M' Arthur's Anti'juities of Arran, p. 90. 



