OVERLYING ROCKS OF ROSS AND INVERNESS. 143 



of the floor in the entrance of Glen Docherty, as nearly as possible in 

 the position indicated in that section, I clearly recognized again 

 during my last visit. It is also seen as we leave the upper end of 

 the glen ; but between these points the ground has been so much 

 broken up by faults passing along the glen and at right angles to it, 

 that it is impossible to trace it continuously. The presence of the 

 old floor in Glen Logan as far as the entrance into Glen Docherty 

 (shown also in Prof. Bonney's diagrams and recognized clearly by 

 him # , and referred to also by Mr. Hudleston in his paper in the 

 Proceedings of the Geologists' Association, 1879) is a fact of so much 

 importance in these inquiries, in consequence of its being found east- 

 ward of the quartzite and limestone series, that the question of its 

 presence in Glen Docherty may be almost dispensed with in the dis- 

 cussion. If the oldest rocks can be seen to rise up anywhere eastward 

 of the limestone series, then the probability of the eastern true 

 metamorphic rocks being parts also of the old floor, as maintained in 

 my former papers, is rendered still stronger, especially if, as I hope to 

 show in this paper, there is abundant evidence tending towards that 

 conclusion. 



I may here also refer briefly to the prevailing faults found in these 

 areas. There can be no doubt, as shown by the directions of the 

 lochs and valleys, that the main faults trend from N.E. to S.W. and 

 from N.W. to S.E. Branching off from these, however, are many 

 minor faults ; but though these are continually met with, they do not 

 usually greatly interfere with the succession, though they occasion- 

 ally cut off considerable thicknesses of strata. Comparatively a few 

 only of the faults are indicated on the map (PL VI.), and those mainly 

 which have a bearing on the questions considered. 



Some of the local names are taken from the recently published 

 Ordnance map ; but the majority are from that published by Black, 

 as they agree with those used in my former paper. At that time 

 the one-inch Ordnance map of these areas had not been published. 

 The numbers on the map refer to the positions of the rock-speci- 

 mens described, and correspond with the notes by Prof. Bonney. 



All the rocks described are from points not referred to in my 

 former papers, and they include all the varieties which appeared at 

 all typical in the traverses made. One section only was examined 

 to the north of the area previously described, the others being all 

 to the south and east. The one to the north may be looked upon 

 as a continuation to the N.E. of the former Glen-Logan sections. 



2. Glen Logan (or Laggan), Upper part. 



The gneiss, note no. 1, has a well-marked strike from N.W. to 

 S.E., and in its general appearance seems typical of the older or 

 what we call the Loch-Maree series. 



About the cottages near the entrance to the glen on the west side 

 leading to Loch Nafatt are exhibited well-rounded surfaces, upon 



* Quart. Journ. Geol. Soc. vol. xxxvi. p. 93. 



