H. COATES AND P. MACNAIR ON BANDED HORNBLENDE SCHIST. 163 
drawn out into these forms during the second or mechanical meta¬ 
morphism and shearing process to which they were subjected. The 
first or contact metamorphism would not probably have much influ¬ 
ence in altering the shape of the granular constituents of the grit, but 
would simply indurate or fuse them together, as we see in more 
recent contact metamorphism, thus tending to obliterate the individu¬ 
ality of each grain and pebble. The difference between a grit which 
has undergone this double metamorphism and one which has simply 
been acted upon by shear and strain is easily recognisable by its more 
altered or mineralised condition. The dark sinuous lines seen in the 
drawing represent a secondary development of pale green mica around 
the grains and pebbles in the grit, and may probably be referred to 
the action of the shearing forces causing the finer argillaceous matter 
of the grits to pass into mica along the gliding planes of the larger 
grains and pebbles. 
Fig-. III. Microscopic Section of Grit Band in Hornblende Schist from Balhoulan 
Quarry. X 50 Diameters. 
Let US now consider how far the theories cited at the beginning 
of this paper to account for the hornblende schists of the Lizard are 
applicable to the phenomena seen at Balhoulan Quarry. At the out¬ 
set, we must put aside any theory based on the supposition that the 
hornblende sehists of the southern Grampians (at least so far as we 
have seen them) were originally stratified ashbeds, thrown down in 
water. Such a supposition is not borne out by the phenomena pre¬ 
sented by these rocks. Admittedly they present strong resemblances 
to the ordinary and undoubted clastic schists, in so far as they are 
curved and contorted in a similar manner, while the folise of felspar 
and hornblende might be compared with those of mica and quartz 
in the mica schists. Further, the felspars often show a granular 
structure, which might easily be taken for that of a truly clastic rock, 
while, to complete the deception, the foli^ and general lie of the beds 
