180 WwW. R. BROWNE. 
inclusions, and of the occurrence of the rock in tongues 
through the schist, indicated its intrusive character beyond 
a doubt. 
The Cooma gneiss.—The Cooma gneiss comes second in 
point of age. The main mass of it, which outcrops in and 
around Cooma, is about 5 miles long, the greatest breadth 
being alittle over 25 miles, but this by no means represents 
the entire outcrop, for isolated patches occur about 5 miles 
south of Cooma, and nearly as far west as Kiaora home- 
stead, in addition to several small outcrops north of the 
town. Besides those occurrences which are definitely 
recognizable as Cooma gneiss there are numerous outcrops 
of crystalline rock which have all the appearance of Cooma 
gneiss which has undergone extreme crushing, producing a 
reduction in the grainsize and a schistose foliation. These 
probably represent tongues or upward injections of the 
original rock into the schists, which in consequence of their 
narrowness have suffered more from mechanical deform- 
ation than other intrusions of greater breadth. Such out- 
crops are to be found at many places among the schists to 
the north and westofCooma. Occasional remains of large 
crystals of felspar or quartz, as well as lenticular inclusions 
of schist, point to the shattering of an original massive 
igneous rock. It seems probable, therefore, that the 
underground extent of the Cooma gneiss is much greater 
than might be determined from the main outcrop 3 in par- 
ticular a considerable extension to the north and west of 
Cooma is indicated. 
The original granite mass from which the gneiss is derived 
must have sent numerous apophyses into the surrounding 
rocks, and this is only to be expected, seeing that the 
invaded formations were probably already cleaved, and 
therefore possessed of planes of weakness, at the time of 
intrusion. These gneissic dyke-like intrusions are fairly 
