420 SOA. GENERAL PESCRIFTIOX. 



SO A.* 



IN describing the red sandstone which occurs near 

 Loch Scavig in Sky, I had reason to regret that its very 

 limited extent prevented me from decidedly tracing its 

 connexion with the other portions of the same rock. That 

 which is found at Loch Sligachan is almost equally obscure, 

 while no correct judgment can be formed from comparing 

 the directions and dips of masses so small and so far 

 separated from each other. Fortunately the island of Soa 

 offers considerable assistance in throwing light on the por- 

 tion which is found at Loch Scavig, as that of Scalpa does 

 with respect to the latter. From these islands also we 

 are enabled materially to extend the connexions of this 

 sandstone, and thus to render the history of Sky as satis- 

 factory, at least, in this respect, as it is in the case of 

 the other stratified rocks. 



This island is about two miles in. length and a mile 

 and a half in breadth, lying about half a mile or more 

 from that shore which forms the foot of Garsven, the 

 southernmost of the Cuchullin hills. It is a low and 

 uneven land of a tolerably continuous elevation, never 

 appearing to exceed four or five hundred feet, and is 

 in general bounded by an abrupt rocky shore ; most com- 

 monly terminating in perpendicular cliffs which do not 

 however exceed sixty or seventy feet in height. The 

 correspondence of the eastern shore with that of the neigh- 

 bouring coast of Sky is so striking as to present immediate 

 conviction of their geological continuity ; an impression 

 confirmed by finding that it consists of the same materials 

 disposed in a manner precisely similar. 



* See the Map of Sky. The illustration which this island offers 

 respecting the structure of Sky has induced me to describe it here, although 

 in strictness appertaining to the Sandstone island*. 



