188 : W. R. BROWNE. 
position relations to the Cooma gneiss, are indicated on the 
map (Fig. 2). They nearly all have an approximately 
meridional trend, and consist of quartz, felspar, mica and 
tourmaline; no other minerals have been recognized mega- 
scopically. Mr.O.F.Laseron, of the Technological Museum, 
Sydney, has kindly given mea piece of rock picked up by 
him near the Cooma pegmatite dykes, composed mainly of 
quartz and epidote. Unfortunately however, the relations 
of this fragment with the pegmatite could not be established 
although there is a strong probability of some connection 
between them. 
Graphic granite is a feature of all the occurrences, and 
there are also coarse irregular intergrowths of quartz 
and felspar. Occasionally a rude ‘“‘comb structure”’ is 
developed by the crystallization of large felspars growing 
towards the centre, the central space being filled with 
quartz. Mica, both white and brown, is developed, the 
latter sometimes being particularly noticeable along the 
sides of the veins with the short axes of the crystals 
parallel to the walls of the intrusion. Tourmaline often 
occurs in large segregations, but may also be irregularly 
distributed: in the Cooma veins the tourmaline occurs 
mostly along the boundary between the comb structure 
felspars and the central filling of quartz. 
There is at times a notable local increase in the basicity 
of the country rock in the vicinity of a pegmatite vein, 
expressed by a concentration of biotite along the margin 
of the intrusion. 
The dimensions of the veins are not in every case ascer- 
tainable, owing to the presence of a covering of soil. The 
occurrence west of Mittagang road appears to be about 20 
feet wide, two others are 15 feet and 6 feet respectively, 
while those in the town of Cooma are not more than a foot 
or two in width. Some of them must have considerable 
