
642  STRATIGRAPHICAL GEOLOGY.  [Boox VI. 
commonly black mica. Kernels of this nature, a foot or more in 
diameter, may be observed on Loch Torridon, consisting of massive 
cleavable hornblende. At this locality also some good examples occur of 
2 structure in the gneiss where certain lamine display a remarkable 



















































































































































































































































































crs 
ae 

= < 
ee = 
BN CPO oy OM yO 
puckering between parallel, not contorted beds (Fig. 318), a structure 
which may be compared with that of many sands and sandstones (ante, 
p. 479). Everywhere the closest union may be traced between the 
— es — 
hyn. aura nba pride daddy avons Neabvandect ea 

Fic. 317.—Fo.iaTION OF A PEGMATITE Vern IN Gyetss, Loch LAXFORD, 
gneiss and the parallel bands of pegmatite, granite, syenite, and other 
massive rocks inter-stratified with it, as if these were not of subsequent 
origin, but were contemporaneously-formed parts of the gneiss. 
Recent observations by Professor Hull and Messrs. Symes and Wilkin- 
