GEOLOGY OF THE COOMA DISTRICT, N.S.W. 18] 
numerous, and a notable 
feature of their occur-‘ 
rence is that apart from @¥_ 
the schistosity due to 2° 
pressure their texture 
differs not from that of 
the main mass of the 
gneiss; in other words 
the original apophyses 
would appear to have \ 
been granitic, and not 
in the nature of quartz- 
porphyry, as might 
reasonably have been 
expected. This may be 
explained by supposing 
that the apophyses are 
really but short offshoots 
from the parent mass, or 
slight upward projec- 
tions from the roof of the 
magma-chamber, so 
slight that the condi- 
tions of their crystalli- 
zation did not differ 
essentially from those 
of the main mass. (See 
fig. 1.) 
4 
7. 
DN 
nD, 
K 
K 
i 
X 
X 
i 
i 
: 
< 
Silarnan. 
Slaves ¥c> - 
se. 
Porphyries 
es Fis 
a 
¢ 
It/ 
- @oul 2r000feelh= 11Nch 
hary 
Basa 
Be 
UU EAOM er, 
Hill 
‘Bushy 
ie 
M'bidgee 
Vertical! scale 
and of the Ordovician and Silurian, ete. 
’ 2Lmiles =s1nch 
Dairymans 
Horizontal Scale 
Inclusions of the in- 
truded schists are fairly 
common in the Cooma 
gneiss in certain places. 
Beyond Mittagang 
' 
‘ 
t] 
‘ 
c 
flary 
Basalt, ooo 
ES Rew, an - 
/ ‘ t 26 ‘I NS 
apes wo at) 
a) Life gee in 
, Piel hate => 
a We Le re Sito Ub 
. .\e ue fey fs awe nt § 
af ieee ane 
ap Se eo in 
‘ Ul . 
r . | 4 thas me <() i 
asi NepRtANEe 
A fey dead NOSES 
ye Penhhes Uglies > 
F aie wt af 
Vests, f\ 
Old vailey of Ck 
rdoviciain 
Slates ke 
Upper M’bidgee 
Fig. 1 —#.W. Sketch section through Cooma, showing suggested relations of gneiss, schist, phyllite and slate, 
Bridge on the Murrum- 
