CRAIGNISH ISLES. GEOLOGY. 271 



north- east. In this respect they correspond with those 

 of the various islands included in this division, as nearly 

 as could be expected from the remarks already made 

 on the lateral deviations of these lines of bearing in the 

 several portions of this extensive group. They present 

 a similar correspondence with the strata of the adjoining 

 mainland, as their leading outlines do with those of the 

 various headlands and inlets to which they approximate 

 in position. The dip of the strata is to the eastward, 

 in which respect they resemble the Slate isles, as well 

 as that part of the mainland with which they are geolo- 

 gically continuous. The angles of inclination are various, 

 but rarely exceed 40, while, in a few instances, they ap- 

 proach much more nearly to the horizontal position. 



The description of the rocks of Shuna already given, 

 corresponds so nearly with that of the Craignish isles 

 in the most essential points, as to supersede the necessity 

 of any minuteness in enumerating those which here pre- 

 vail : these details, like the history of their connexions, 

 will be better reserved till all the associated islands have 

 been described. The principal rocks are quartz rock of 

 various characters, micaceous schist, and chlorite schist 

 under several distinct modifications.^ Of these, the latter 

 is the predominant, occupying perhaps three fourths of the 

 whole space, the quartz rock bearing the next propor- 

 tion, and the micaceous schist scarcely amounting to one 

 twentieth of the whole. Occasionally the chlorite schist 

 contains hornblende or actinolite, and thus gradually passes 

 into an hornblende schist, or into an actinolite schist, of 

 various aspects. These several substances alternate in fre- 



* Where this schist is subject to the action of the sea, it presents 

 shallow cavities strongly resembling the impression of a human foot. 

 It is more remarkable that these are sometimes placed alternately in 

 parallel lines, so as to resemble a series of the steps of an individual. 

 As the Scythians showed an impression of the foot of Hercules, the 

 Highlanders may be allowed the same indulgence for the footsteps 

 of Fingal. 



