142 DR. H. HICKS ON THE METAMORPHIC AND 



In a former paper* I placed the axis of the oldest rocks in the 

 direction of Loch Maree, with newer beds to the sonth west at Gair- 

 loch and to the north-east about Ben Fyn. In doing this I did not 

 necessarily mean to correlate the series at Gairloch with those of 

 Ben Fyn, but believed them to be so closely allied that they could be 

 easily included in one great group. The more hornblendic varieties 

 along the shores of Loch Maree and the granitoid rocks south of 

 Poolewe were, in my opinion, of older types ; but whether separated 

 from the former by actual unconformity or not I was unable to say. 



Without referring again to the several views maintained in regard 

 to the metamorphic rocks in the eastern areas, with which I have 

 chiefly to deal, it is clear, as specially bearing upon those views, that 

 the following points have to be kept constantly in mind in these 

 inquiries. (1) Is the stratigraphical evidence as to a continuous up- 

 ward succession, maintained by Murchison and Geikie, of that conclu- 

 sive character that it must overthrow all petrological evidence which 

 may seem to render this, if not impossible, yet highly improbable ? 



(2) Has this upward succession from Torridon Sandstone through 

 the quartzite and limestone series anywhere been observed to gra- 

 duate into gneiss rocks of the type such as we classify under the 

 name Ben -Fyn series. 



(3) Are not the flaggy micaceous rocks, such as those which we 

 have described from the east side of Glen Logan, which probably 

 overlie the limestone series (though there undoubtedly separated 

 from the latter by a fault), more intimately allied in their microsco- 

 pical and general characters to the Torridon series than to those of 

 the Ben-Fyn type, which they are supposed to immediately underlie? 



(4) Are there evidences of the disturbance of the strata by faults 

 and inversions along these lines of such a kind as would be likely to 

 greatly interfere with and to complicate the order of succession ? 



(5) Do the eastern metamorphic rocks show at different horizons 

 and places that variability in the amount of alteration which is 

 usually noticed in rocks subjected to local influences only ? or do they 

 not rather everywhere show an identical state of alteration, as if the 

 result of some wide-spread cause, rather than due to local mechanical 

 disturbances ? 



Before proceeding to describe the various sections examined since 

 my paper was read in 1878, I may here take the opportunity of 

 referring to a point in connexion with the section published in 

 that paper which needs some explanation (though I have to a certain 

 extent done so in my paper in the Geological Magazine, 1880). In 

 that section the beds were accidentally placed at too high an angle in 

 the part east of Glen Logan, and the floor made to appear to continue 

 too uninterruptedly eastward. The published section, however, as 

 mentioned in the discussion, was intended merely as a diagram ; 

 the views that I entertained were fully explained in the text f. Yet 

 as it might tend to give a misleading idea as to the condition of the 

 floor at this part, I think this explanation necessary. The presence 



* Geol. Mag. Dec. ii. vol. vii. 1880. 



t Quart. Journ. Geol. Soc. vol. xxxiv. p. 816, 



