328 PROCEEDINGS Of THE GEOLOGICAL SOCIETY.' [Feb. 26, 



lower fall, to an enormous depth. The basaltic sheets here also bear 

 the same evidence to their later origin than the Oolitic deposits in 

 the marked changes they produce on the sedimentary strata. 



This central depression between the lofty cliffs on the shore and 

 those of the range of the Storr, and in which the fossiliferous beds 

 have not been before noticed, has a gentle diagonal swelling towards 

 its southern part, almost due west from the top of Tor-vaig, which 

 sends its waters to either side, north to the lakes and south to Portree. 

 This summit-level is formed of trap, which extends thence to Portree, 

 the fossiliferous beds not forming any connexion southwards with 

 those of the shore-line. A considerable burn, whose lower course 

 is through a deep trap gorge into the inner harbour of Portree, flows 

 in its upper course close by the. base of the Storr range, having its 

 source in a lateral-glen opening upon the summit-level ; and here, 

 by its edge and in its bed, are several large blocks of the fossiliferous 

 sandstones of the Oolite. The bed and banks consist entirely of 

 huge sheets of trap ; and the sandstone blocks are plainly not in situ. 

 They must have been borne down in floods by some of the side burns 

 already alluded to as showing these sandstones, or else transported 

 hither by ice-action ; some, indeed, appear too large for the trans- 

 porting power of the burns even in heavy flood. The huge sheets 

 of trap just mentioned have their surfaces both in the bed and 

 banks, covered with fine markings such as are usually ascribed to 

 the action of ice ; they are nearly transverse to the course of the 

 burn, ranging N.W. and S.E. (true), and tberefore can hardly be 

 ascribed to the action of stones borne along by the stream. It is a 

 rare thing for trap surfaces in this district to bear such striae. 



The Loch-Stafitst Beds. 



Northward from the great waterfall, nearly opposite Holm Islet, 

 the cliffs have but slight elevation, and the secondary beds, which are 

 those of the middle and lower Oolite, small development. At Eu-na- 

 Bhrarin there are great trap intrusions, and the beds are cut off by 

 trap rocks occupying the shore-line (see map and sections, PI. XI.) ; 

 a little further north, however, not far from the waterfall of Loch 

 Me-alt, the cliffs increase in height from the on-coming of beds 

 higher in the series and a greater depth in the basaltic covering. 

 These higher beds are those which have been called the Loch-Stafnn 

 beds (Murchison & Forbes, ut supra), but which are now known, 

 as above described, to occur in the Portree Section, and one bed at 

 least in Baasay. A brief notice only is here required, and that 

 mainly with the view of justifying our dissent from certain theore- 

 tical conclusions advanced by Professor E. Forbes. 



The sea-line and tideway at Loch Staffin, and for many miles 

 south-eastwards, unless where faults bring down the upper beds, 

 are formed of a coarse crystalline dolerite consisting of felspar and 

 augite, and sometimes dipyre : it .is very hard and tough, and 

 almost as rough on the worn surfaces as the hypersthene of the 

 Coolinsj it weathers a rusty brown, the colour being much deeper 



