186 W. R. BROWNE. 
This amphibolite must be taken to represent an original 
dioritic or gabbroic rock intruded subsequently to the 
Cooma gneiss, but anterior to the large pegmatite veins. 
The pegmatites.—Pegmatite veins are distributed very 
widely among the crystalline metamorphic rocks, but in 
spite of this their relations to the surrounding rocks are by 
no means Clear in all cases. There have been three sepa- 
rate igneous intrusions in connection with which pegmatites 
might have been injected. With regard to the blue gneiss 
no evidence has been found to show that there was a proper 
pegmatitic phase of the intrusion: it is different with the 
others. The schists, particularly to the south and west of 
Cooma, are in places very strongly injected with pegmatitic 
material. Owing to the fact of the mottled gneiss and the 
Cooma gneiss having been intruded over very much the 
same area, it is often impossible to tell to which intrusion 
these injections aredue. Furthermore, both of the igneous 
gneisses have themselves been subjected to pegmatisation. 
This may be observed in the bed of Cooma Creek a few 
miles north of Cooma, at the head of Snake Gully near 
‘**Kiaora,’’ and elsewhere. Long veinlets of pegmatite 
follow the lines of foliation of the gneiss, occasionally 
bulging out into lenticular masses. The sedimentary 
schists have been similarly affected, the little pegmatite 
stringers being very numerous, and following the puckerings 
and foldings of the schist. These veinlets are as a rule 
narrow, varying in width from 4 of an inch up to a couple 
of inches or so, although some in the Cooma gneiss attain 
a width of 6 inches. They consist for the most part of 
quartz and flesh-coloured felspar, with subordinate white 
mica and black tourmaline. 
Apparently distinct from these minor pegmatites, there 
have been observed a number of larger and more truly 
pegmatitic injections. The principal of these and their 
