203 
dence of having undergene rejuvenescence before the shatter- 
ing took place. The individual grains have crenulated mar- 
gins and are completely interlocked. Numerous small, per- 
fectly round grains of zircon are present. 
жк Ме е s Hill 
Macroscopic character s.—Exactly similar to 
those of xx., though the colour is somewhat more pinkish. 
Microscopic characters.—vVery similar to 
those of xx. In addition to quartz, the rock contains very 
small amounts of muscovite, biotite,. apatite, zircon, and tour- 
maline, and is somewhat iron-stained. Evidence of crush is 
slightly less marked. Lines of inclusions pass continuously 
through adjacent grains. Dovetailing of grains, etc., as in 
xx. Secondary quartz veins pass through the rock; their in- 
jection must have been prior to the later part of the period 
of crushing (Plate xxxiii., fig. 6). Strong tendency to cleavage 
іш the rock. The similarity between this rock and the pre- 
ceding one is remarkable, as they come from two entirely 
different geological horizons. Upper Sturt is in the lowest 
portion of the Mount Lofty series, while Sellick's Hill is in 
the purple slate formation, the topmost formation in the 
series. 
i Là ыш nda. 
The geological horizon of this rock has not been satisfac- 
torily determined. The quartzite is associated with a very 
extensive series of tremolite-, actinolite-, andalusite-, and 
mica-schists, crystalline limestones, and coarse gneisses. 
Macroscopic character s.—Intensely white, 
saccharoidal quartzite, of rather coarse grain, with bands of 
still coarser, clearer material. Fracture around the grains 
in finer, across the grains in the coarser, portion. 
Microscopic character s.—Coarse-textured 
aggregate of quartz, with every evidence of intense strain. 
Grains completely shattered. Abundant liquid and gas cavi- 
ties, the former with slow-moving bubbles. Strong tendency 
for the cavities to be arranged in lines continuous through 
adjacent grains. A few rounded flakes of biotite occur in 
the quartz and in some fragments numerous excessively fine 
rutile (7) needles. 
xxiii Mount Barker, northern end of the mount. 
Macroscopic characte rs.— Medium-grained, 
hard white quartzite, very tough, and breaks with a con- 
choidal fracture. Slightly micaceous. 
Microscopic character s- Texture medium. 
Essentially an aggregate of very irregular quartz granules, 
with 2-3 per cent. muscovite in large flakes, some pyrite, 
