144 OUTLINES OF FIELD-GEOLOGY PART i 



forming the summit of the hill cousin <>f Archaean 

 (Lewisian) gneiss. The white cliff is formed of well- 

 bedded quartzite, dipping gently southward under the 

 summit of the hill, lying unconformably on the Torridon 

 sandstone below, which in turn rests unconformably on 

 the Lewisian gneiss. The structure of the hill is i 

 sented diagrammatically in Fig. 41. It will be observed 

 that the portion of the older rocks displaced includes 

 parts of the double unconformability, and that the 

 rocks have been driven over and folded by a movement 

 from S.E. 1 



1 For an account of thrust-planes and numerous sections illustrat- 

 ing them see the Geological Survey Report in Quart. Journ. Gcol. 

 Soc. vol. xliv., 1888, p. 378. 



