349 



THE OTHEE CLYDE ISLANDS. 



INCHMARNOCK. 



150. This small island lies on the western prolongation of 

 the outer slate band which crosses Bute, and is noted for its 

 quarries of roofing slate. 



GREAT CUMBRAE. 



151. This island is three miles long and one and a-half 

 broad; the surface rises gently towards the middle, and the 

 height nowhere exceeds 500 feet; the southern shore presents 

 some low rocky cliffs; on the other sides the ground descends 

 by grassy slopes and sandstone ledges. Wanting trees and 

 streams, and without lofty rocks, the island has little variety 

 of scenery; bxit the views to be had from almost every 

 part of it are of surpassing magnificence and beauty. Great 

 Cumbrae corresponds in geological structure with the middle 

 region of Bute, and consists of red sandstone, having a slight 

 northerly dip, traversed by numerous trap dikes, invaded 

 by sheets of the same rock, but not overlaid by trap except 

 in one spot on the west coast, where a small patch occurs. 

 The sandstone is generally of a deep red colour; almost the 

 only exception being found in the small islets forming the 

 harbour of Millport, which consist of white and gray sand- 

 stone. Strata of conglomerate structure are occasionally 

 met with, and the ridges on the west formerly shewed some 

 thin limestone beds interstratified with the sandstone, but 

 these have been worked out. No fossils have been met 

 with ; but there can be little doubt that the sandstone is of 



