xxvi. Waterfall Gully, about one mile from 
Burnside. 
Macro scopic Ota nate Urs, OG veenisH" grey 
rock, composed of fairly coarse, clear quartz grains, set in а 
finer-grained groundmass of the same substance, mixed with 
dark-greenish chlorite material. 
Microscopic Waru cter 's.—Moderately fine 
in general texture. Grains are subangular to rounded, and 
there is a moderate amount of interstitial cement. The chief 
constituents are quartz and felspars of the same types as 
those in the Mitcham rocks. They mostly show evidence of 
strain, and the felspars are rather decomposed. Some of the 
quartz shows abundant mica flakes as inclusions. There is a 
little magnetite in crystals, and some tourmaline and rutile. 
In addition to these constituents there are locally numerous 
minute rhombic sections of a mineral with moderate refrac- 
tive index and strong double refraction. These are pleo- 
chroic, from blue to colourless. These characters and the 
measured angles of the sections suggest lazulite. This is the 
only rock in which I have been able to detect any mineral 
resembling lazulite, although Rosenbusch* states that this 
mineral is particularly characteristic of quartzites. The ce- 
menting material is mostly a dark green, almost isotropic 
delessite, though there is also a good deal of kaolin stained 
with iron oxides. (Plate xxxiv., fig. 1.) 
xvin. Charen dons Tunnel 
Macroscopic character s,—Greenish rock of 
moderately coarse texture, composed mainly of quartz, with 
some felspar, set in dark-green chloritic base. Much pyrite. 
Microscopie characters. —Texture medium. 
Chief constituents are quartz, felspars, composite grains. 
The quartz contains numerous gas and liquid cavities, and 
inclusions of apatite, actinolite, rutile, and zircon. Compo- 
site grains are mostly rather coarse mica schist. Interstitial 
material is mostly dark-green delessite, with a little sericite. 
Much pyrite and a little tourmaline and apatite are present, 
and also patches of opacite. 
xxix. Coromandel Valley, near Blackwood. 
M. 0 6 s 048.01 0XD.240 character s.-—Fine-grained, 
white, hard quartzite, with numerous whitish patches. 
Microscopic characters.—Rather fine in 
texture, composed mainly of quartz, with a little felspar, 
fragments of biotite schist, a good deal of sericite, and only a 
little chloritic material. Some of the quartz grains are 
crowded with radiating bundles of tremolite. The most 
striking feature of the section is the abundance and variety 
* Rosenbusch: “Mikroskopische Physiographie," ed. 3rd, p. 500. 
