196 
ividiower be dj Watert all Cull y; forming 
lip of fall. 
Macroscopic characters.—Medium grained, 
very vitreous, pinkish quartzite, with a good deal of hæma- 
tite staining. Felspar fragments as in the preceding rocks. 
Fractures across the grains. 
Microscopié emaracter s.—Moderately coarse 
in grain, though not so coarse as i. Mineral composition 
like i., but relatively less felspar. Felspar shows little trace 
of idiomorphism. Quartz exhibits much strain structure, of- 
ten amounting to complete peripheral granulation. Secon- 
dary overgrowth of rounded quartz grains very marked. 
Planes of inclusions (gas and liquid) cut through adjacent 
grains. Some of the quartz grains contain excessively fine 
rutile (?) needles. 
Composite fragments as in the preceding rocks. "There is 
little sericitic material except in direct association with fel- 
spar grains. The sericitic areas, cleavage cracks in the fel- 
spars, and similar absorbent portions of the slide are strongly 
stained by iron oxides, and the pyrites of the preceding rocks 
is here represented by hæmatite pseudomorphs. 
ev material Gully. 
Very Wass ve. bed „ab. upper fall 
Macroscopic character s.—Rather fine-grain- 
ed, intensely hard, vitreous quartzite, very much jointed, 
fracture conchoidal. 
Microscopic characters.—Quartz much the 
same as in iv., but much less felspar, sericite very much more 
abundant. Cherty fragments rather abundant, and amongst 
other composite grains those composed of quartz and miero- 
cline are important. 
In parts the rock consists essentially of a mass of angular 
and subangular quartz grains, set in fine sericitic ground 
mass. Strain structures in the quartz amount to complete 
shattering, but do not approach thorough granulation. Re- 
juvenescence of quartz grains marked. 
vi. Gumeracha (exact locality not known). 
Macroscopic character s.—Strongly pyritic, 
grey quartzite, very vitreous on fracture. Felspathic con- 
stituents not so prominent as in the rocks near Adelaide, as 
they are more colourless. 
Microscopie characters.—Texture medium. 
‘About 30 per cent. felspar, rest chiefly quartz. There is a 
good deal of authigenic pyrites. Very subordinate amounts 
of biotite. Composite grains not recognisable with certainty 
on account of the intense crush. 
