68 Dr. Mac Culloch's Sketch of the 



in the durability of these mountain greenstones and those of the 

 stratified trap, or of forming any probable conclusion respecting their 

 asras of formation. Much remains to be learnt before we can attain 

 to an accurate knowledge of these rocks, and there Is much yet re- 

 maining for future observers In the ground which I have now trod- 

 den. But It is not an easy task to ascend these pinnacles and to 

 traverse this rocky desart even in summer, and summer seems 

 never to shine on them — at least it has never yet shone for me. 



I must now proceed to consider the last rock which remains un- 

 described, the Syenite. 



In describing the CuchuUin, I have for the sake of contrast in- 

 troduced so many of the most remarkable features of the other 

 group, which I have distinguished by the name of the Red Hills, 

 that the less will remain to be said respecting them. They are in- 

 variably characterized by the lumpish roundness of their outline. 

 The cause of this consists evidently in their rapid decomposition, 

 and in the accumulations of fragments which cover not only their 

 sides but their summits so completely, as to preclude in most places 

 any view of the naked rock. Their elevation I have formerly ob- 

 served is much less than that of the Cuchullin, and I have also 

 remarked that they form a separate assemblage, interfering at their 

 bases only by indentation or approximation, and being always dis- 

 tinguished from the latter both in character and composition. The 

 summits most convenient of access are those of Ben-na-Cailllch near 

 Broadford, with Its dependencies, and the somewhat insulated moun- 

 tain of Glamich above Sconser, the highest of the group. As Ben- 

 na-Caillich presents the greatest simplicity of composition, I will 

 describe it first. It forms part of a group which descends into the 

 plain by various acute ridges, reaching into Strathmore and the head 

 of Loch Slapin on the southern side, and extending towards Scalpa 



