412 PROCEEDINGS OF SECTION C. 
-described, but to be less fine-grained, and with more secondary 
quartz diffused through it, as well as in narrow reticulated veins. 
The induration of these sediments is due to silicious infiltrations, 
which may have been connected with the intrusion of the 
porphyrites. On the further side of these the sediments are 
much contorted in places, but are somewhat less indurated and 
more schistose. At about one hundred and twenty chains the 
probable strike is to the north-eastward, with a dip of 80 deg. to 
the south-east. Narrow strings of quartz appear in and across the 
foliations. Under the microscope, the rock is seen to resemble in 
mass those already described, but, in addition, to be traversed by 
numerous winding, although on the whole parallel, partings lined 
with flakes of a pale yellowish mica, indicating the commence- 
ment of a foliated structure produced by pressure. In parts of 
the rock, where there are some larger elastic grains of quartz, 
these foliations wind round them, forming ‘“ eyes” in the same 
way as I have described in the pressure gneisses near Omeo. 
At about 160 chains the rocks are distinctly more schistose, 
with little traces left of bedding. Under the microscope, it is an 
irregularly foliated rock, composed of flakes and small crystals of 
colourless mica, with a lesser amount of biotite in larger, but 
irregularly formed plates and crystals. At this point I observe 
a decided change in the character of the schists. 
Those adjoining are very silicious, and are composed of quartz 
grains full of minute fluid cavities and microliths. The grains of 
quartz which form the greater part of the rock have not the 
appearance of elastic quartz, and are separated in places by small 
foliations of minute flakes of biotite. Further on, at about 230 
chains, the schists are also extremely quartzose. They are formed 
of foliations of quartz grains, between which are narrow foliations 
of detrital materials, some part of which is felspar, with a little 
mica, and a comparatively large percentage of epidote. The 
narrow detrital foliations swell out in places, round small 
masses, which can be regarded as altered felspars. Immediately 
adjoining these rocks are gneisses, composed of foliations of 
orthoclase and plagioclase, which are rounded, in places fractured, 
but not stretched or distorted. As is usual in such cases, they 
are all more or less surrounded by margins and endings of 
detritus, that is, of rubbings of felspar and quartz. Flakes of 
biotite line the most marked planes of separation. Besides the 
lesser quartz grains, there are also foliations of quartz, which in 
places bend round the inclined felspars, or larger quartz grains. 
In places the quartz has undulatory extinction. Some samples 
of these rocks show typical examples of such crystalline schists. 
Finally, where the track crosses the first branch of Marengo 
Creek, there are massive quartz diorites composed of biotite mica, 
triclinic felspar (oligoclase) and quartz. These diorites extend 
over a large area, and from them might be produced just such 
