32 
Geology and Physical Geography: 
the Upper Palaeozoic sandstones of the Dundas Range, and are, 
therefore, clearly of older date, probably Silurian, or possibly 
of the Cambrian or Laurentian series. No actual gold workings 
have been opened, though small prospects of gold are reported to 
have been obtained from both alluvial deposits and quartz reefs 
within this area. 
The metamorphic rocks of the North-Eastern district, which 
includes Omeo and other gold-fields, afford fine opportunities for 
examination, as gradations of structure are in many places easily 
traceable on the surface, unconcealed by any overlying deposit. 
The best observed tract is that extending from the Dargo River, 
near May ford, to Mount Bogong in one direction, and to Oiueo 
and Mount Tambo in another. On the western slope towards, and 
in the bed of, the Dargo River at May ford, are the normal Silurian 
slates and sandstones. 
From Mayford, towards Bogong or Omeo, a gradual change is 
observable in their character ; the ordinary rocks pass into silky 
micaceous schists, followed by mica-schist, gneiss, and gneissose 
granite, finally merging into granite which yet shows occasionally 
a rudely-schistose structure, indicative of its having been once in 
the form of a stratified rock. Similar gradations aro observable 
all round this metamorphic area, of which the Bogong Range is 
the most central granitic mass, though there aro several other 
granite tracts that appear either to represent foci whence radiated 
the metamorphic influences which altered the Silurian rocks, or, at 
all events, to bo the extreme results of these influences. Besides 
the common gneissose and micaceous schists, there are in the 
Chiltern, Omeo, Bogong, and Mitta Mitta districts many varieties 
of metamorphosed stratified rocks, such as nodular micaceous 
schist, chiastolite schist, Ioptynite schist containing garnets, 
hornblende schist, and others. 
In some cases, the altered rocks agree in general direction of 
strike with the unaltered, but in others the former show extreme 
contortion, and their strike varies greatly from the normal direction. 
Numerous dykes and injected masses of porphyry, greenstone, 
diorite, &c., showing great diversity of mineral ogi cal structure, 
intersect the metamorphic schists throughout the Omeo district. 
At Stawell, and near Ararat, occur small belts, about a mile in 
width, of metamorphic rocks, consisting — as described by Mr. 
Norman Taylor in his report upon the Stawell gold-field (Geo- 
logical Progress Report, No. II.) — of foliated gneissose schists, 
passing into true gneiss, composed of alternating layers of felspar, 
hornblende, and quartz, hornblendic gneiss, and other varieties. 
Some of the metamorphic rocks of Stawell, however, differ 
very little from the normal Silurian strata, except in being gener- 
ally more indurated and foliated than the latter. 
