162 LUNGA. GENERAL DESCRIPTION. 



LUNGA.' 



THE principal islands which have just passed under 

 review, consisting of Kerrera, Seil, Luing, Torsa, and 

 Shuna, are so nearly associated in structure as well as in 

 position, so that they have been considered as forming a 

 subordinate group in the more general one that includes 

 the whole of the Schistose isles. They have already also 

 been distinguished by the title of the Slate isles, being the 

 name by which many of them are popularly known in the 

 country. 



The four next to be described, namely, Lunga, Scarba, 

 Jura, and Isla, are equally associated by a common geologi- 

 cal bond of union ; the predominant features of which are, 

 the prevalence of a continued line of quartz rock, and the 

 frequent alternations of this substance with micaceous 

 schist, clay slate, and graywacke. In a geographical view 

 they are equally connected; forming a chain of considerable 

 length, although its constituent parts are of very unequal 

 dimensions : they have therefore been combined into 

 another subordinate group. The analogy between them 

 will be found to extend to the disposition of their strata 

 and the forms of their shores ; but as these several points 

 of relation will be best understood after they have been 

 described, I shall defer the general comparison till then, 

 commencing here with Lunga and proceeding southwards 

 to Isla. 



So intimate is the geographical connexion between 

 Lunga and Scarba, and such the continuity of structure, 

 that a perfect description of the one would, in a geological 

 view, leave little to add respecting the other. It will 

 indeed hereafter be seen, that the same structure is pro- 

 tracted, with scarcely any change, to the northern part of 



* See the Map of the Slate isles and also the General Map. 



