SKY. GEOLOGY. SECONDARY STRATA. 353 



part of the island. This irregular mass commences at 

 the northern side of Strath, at the upper boundary of 

 the limestone series, and terminates partially at Loch' 

 Sligachan, being succeeded for a small space by a 

 second portion of stratified substances. These are again 

 interrupted by a second mass of unstratified rock, which 

 although thus divided on the eastern side of the island, 

 unites into one continuous mountain mass at a small 

 distance westward. On the eastern coast, immediately 

 succeeding this portion of unstratified rock, a sandstone 

 totally disunited from all the former strata appears ; 

 being repeated with similar interruptions for a consider- 

 able distance along this shore, and finally appearing on 

 the western side of Trotternish under equal circumstances 

 of irregularity.^ 



The chasm in the strata thus produced here by the 

 unstratified rocks, is filled by Rasay, Scalpa, and 

 Pabba; and a series may thus be traced among the 

 several islands, scarcely perfect in any one, but most 

 continuous in Rasay; while in Sky it is so interrupted 

 as to be undeterminable without their assistance .f The 

 order of the whole is as follows ; gneiss, red sandstone, 

 gryphite limestone, white sandstone, limestone, and shale ; 

 the intermediate alternations being neglected for the 

 purpose of condensing the series. In thus replacing the 

 scattered parts, the white sandstone of Trotternish becomes 

 approximated to the inferior limestone, and restores that 

 continuity which the present statement was intended 

 to establish. It may be added that the order thus 

 circuitously traced on the east side of Sky is more 

 visible on the west, where the immediate sequence of 

 the upper sandstone to the gryphite limestone has so 

 lately been described. 



It is next necessary to inquire respecting the resem- 

 blance of these to analogous rocks found in other places. 



* PI. XIV. ftg. 1. f PI. XV. 



TOL. I. A A 



