GEOLOGY OF THE COOMA DISTRICT, N.S.W. 177 
Slack’s Creek phyllites.—Along the western side of 
Dairyman’s Plain, as has been mentioned, the appearance 
of the schists changes; quartz no longer appears mega- 
scopically, the chief visible constituent being mica, and the 
rocks grade into shimmering micaceous phyllites. These 
may be named the Slack’s Oreek phyllites,* from their 
conspicuous development there. A traverse westward from 
Kiaora homestead exhibited well the variations of these 
rocks. Succeeding the crystalline schists, very shiny mica- 
phyllites predominate. These are finely corrugated and 
highly cleavable. Closely associated are rocks of generally 
similar character, but more coarsely corrugated, and 
roughened by knots of (?) incipient andalusite. These 
knotted phyllites are very frequent in bands of a few inches 
to a foot thick: the boundaries between them and the 
bands of plain and finely corrugated phyllite are very sharp, 
and two varieties can readily be obtained in the same band 
specimen. 
Interbedded with the phyllites (for the planes of schis- 
tosity have also been bedding-planes) are bands of a hard 
dense dark blue quartzite or quartzitic schist, often a couple 
of feet or more in width. These quartzites also occur as 
lenticular bands about 3 or 4 feet long and 4 or 5 inches 
thick. 
The prevailing dip of the phyllites is easterly and varies 
considerably in amount, from a very high angle down to 
about 30°. 
Just about where the Dry Plain road crosses Slack’s 
Creek there can be seen a black micaceous slate inter- 
bedded with the phyllites. Further up the creek, about 
2 The term phyllite has been objected to in view of the plainly 
autogenic character of the rock, but the name has been considered neces- 
sary on account of the markedly micaceous character of the rock as com- 
pared with the schists. 
L—July 1, 1914 
