On Slaffa. 449 



It is superfluous to attempt a description of the great cave. 

 The language of wonder has ah-ea<ly been exhausted on it, and 

 that of simple description must fail in an attempt where hyper- 

 bole has done its utmost. I may however remark, that its di- 

 mensions appear to have been over-rated, in consequence of the 

 mode of measurement adopted, and that the drawings of it 

 which have been engravetl, give it an aspect of geometrical re- 

 gularity which it is far from possessing. Its superiority in point 

 of effect to the greatest efforts of architecture, might admit of 

 dispute if there were any disputing about feelings. Another cave 

 occurs at a short distance westward, of inferior dimensions, and 

 inaccessible unless when it can be entered jn a boat, an event 

 requiring a combination of circumstances of no very common 

 occurrence at Staffa. Large fissures are seen above this cave, 

 with an incipient detachment of considerable masses, tlu'eatening 

 a ruin which is perhaps not far distant. Beyond this there is 

 still another cave which appears to pass through the promontory 

 in which it lies, but equally or even more difficult of access, and 

 still involved in uncertainty. Many other caves of less note are 

 to be seen in various parts of the cliff around the island, into 

 ■xVhich the sea breaks with a noise resembling that of heavy and 

 distant ordnance. 



In a letter transmitted last year to the Secretary of this So- 

 ciety, I took notice of a fact of consideral)le importance in the 

 natural history of tliis island, which had before escaped the re- 

 marks of visitors. This is, the occurrence of a bed of alluvial 

 matter on some parts of its surface, containing fragments of the 

 older rocks. It is most easily seen at that side of the island 

 which faces lona, and on the summit of the cliffs of a' semicir- 

 cular bay opening in that direction. The bed is here broken at 

 the edge of the cliff, so as to expose its whole thickness for a 

 considerable extent. But the same appearance may also be ob- 

 served immediately above the ordinary landing place, where the 

 bed has also been broken. The stones which it contains are all 

 rounded, and of various, often considerable dimensions, and they 

 exhibic specimens of granite, gneiss, micaceous schistu:*, quartz, 

 and red sandstone. Together with these, are some rolled pieces 

 of basalt. 



Here then is a circumstance in the mineral history of Staffa, 

 adventitious it is true, but involving difficulties of no small im- 

 portance. If we cast our eyes on the map, we shall per- 

 ceive that it is embayed in a large sinuosity formed in the 

 island of Mull, and nearly inclosed on the opposite side by lona 

 and the Treshanish iblands. Beyond the latter, a second line is 

 drawn by Tirey and Coll ; while to the north, but at a greater 

 distance, are placed the islands of Muck, Rum, Egg, Canna, and 



Vol.44. No. 200. Z)ec. 1^14. Ff Sky. 



