m THE NORTH-WEST HIGHLANDS OF SCOTLAND. 



421 



anticline. Along the western side of the arch, where the quartzites 

 and limestones dip to the west, the thrust-planes are inverted, so 

 that the observer has, metaphorically, to stand on his head to realize 

 the effect of the displacements. 



Geological Structure of Ben More. — Along the line of complicated 

 structure between Eriboll and Ullapool, Ben More stands unrivalled 

 for the extreme intricacy of the geological relations of the strata, 

 for the striking evidence in proof of the existence of two maximum 

 thrust-planes, and finally for the brilliant light which it throws on 

 the metamorphism induced by these mechanical movements. 



This mountain has two peaks, one, Ben More (3273 ft.), the other, 

 about a mile to the west, named Coinne-mheall (Coniveall) (3234 feet). 

 Between the latter peak and Braebag there is a col or narrow pass 

 termed the Bealloch, separating the head-waters of the Oykel from 

 the sources of the Traligill. In order to illustrate the structure of 

 the mountain, we propose to describe three horizontal sections 

 traversing it in various directions (figs. 15, 16, 17). 



Fig. 15. — Section across Ooinne-mheall from one of the sources of 

 the Traligill east to Corrie Mhadaidh. (About 1^- mile in length.) 



S.W. Coinne-mheall, IS^.E. 



Fig. 16. — Horizontal Section from the Bealloch across Coinne-mheall ^ 

 to Corrie Mhadaidh. (About l^- mile in length.) 



8.S.W. Coinne-mheall. N.N.E. 



Beginning at the base of the western slope (fig. 15), both the zones 

 of the quartzite, the false-bedded grits, and " pipe-rock " are driven 

 on to the Silurian limestone by the Glencoul Thrust. Ascending the 

 slope, the false-bedded grits are made to overlie the " pipe-rock " by 

 means of a reversed fault, and for some distance upwards, to near 



