814 



H. HICKS ON THE METAMORPHIC AND 



except where it approaches or is in contact with an intrusive mass, 

 is everywhere in an nnaltered state. In all sections across Glyn 

 Laggan hitherto described a great mass of intrusive rock is shown 



Pig. 2. — Section across Glyn Laggan, about tivo and half 



of Kinloch Etve. 

 N.W. 



N.E. 



S.E. 



For explanation of symbols, see fig. 1. 



to separate the limestone entirely from the upper series of rocks (the 

 so-called Upper Gneiss), and hence to occupy most of the low ground 

 between the heights on either side. This, however, on careful ex- 

 amination, proved not to be the case ; and a second series of sand- 

 stones, calcareous grits, and blue flags (e) were found to occupy the 

 bed of the river and a considerable distance of the sloping ground 

 on either side (see fig. 2). 



Another arm of the invading mass* rises up to a height of 230 feet 

 on the east side, and may be examined in the Denlochie torrent in 

 contact with the next series. Prof. Nicol places a fault at this 

 point, and says that the fundamental gneiss (a) is here brought up to 

 give it an appearance of overlying conformably the unaltered series. 

 I, however, hold, with Sir R. Murchison and Mr. Geikie, that the 

 next (/) is a younger series, and that it overlies the unaltered 

 beds ; but I entirely demur to the view held by them that the 

 rocks which compose this group as exhibited here should be 

 called gneiss rocks, or associated in any way with those which 

 have undergone the metamorphic change so characteristic of the 

 pre-Cambrian rocks as known in this country, and which could 

 only be induced, I believe, by influences to which it is evident these 

 rocks, as shown by their position and undisturbed state, could not 

 have been subjected, and which would occur mainly during periods 

 of great depression combined with heat, moisture, and pressure. 



* This invading mass varies considerably at different points, and 'it becomes 

 difficult to give it everywhere a distinctive name. The term syenite, however, 

 though not quite satisfactory, is, according to my friend Mr. Hudleston, the best 

 general name. 



