Met amorphic Roclcs and Crystalline Schists . 
31 
schists, classed as Azoic from the non-discovery hitherto of any 
fossils in their layers, though probably of Silurian age as regards 
their deposition. 
Metamorphic Rocks and Crystalline Schists. 
Strictly speaking, all rocks composed of consolidated sedimentary 
deposits have been metamorphosed, inasmuch as their present con- 
dition is very different from what it was when they were first laid 
down in the form of silt, mud, sand, gravel, or precipitates, owing 
to the long-continued influences of pressure, heat, hydrothermal 
and chemical action; but the term “ metamorphic” is here specially 
applied to certain groups of rocks, which appear to be the extreme 
products of this process of transmutation, and may be divided, as 
indicated in Mr. A. W. llowitt’s work, previously referred to, into 
two kinds, “ regional ” and “ contact.” 
The character of the first appears to be the result of long- 
continued metamorphic action radiating for great distances and 
gradually decreasing outwards from central foci. The precise 
nature of this action is still a matter of conjecture, but it appears 
to have been different from that which operated in the case of 
the “ contact ” metamorphic rocks in which the metamorphism is 
more local, and is evidently the effect caused by intrusions or 
invasions of the sedimentary strata by igneous masses, the influence 
of which did not extend very far and did not continue long in 
activity. 
In fact, it is frequently found that the “regional” metamorphic 
rocks have been further and subsequently affected by “contact” 
metamorphism at their planes of junction with the granites and 
trap pea n rocks. 
Of the two great “ regional ” metamorphic areas in Victoria, 
one is situated between the Wannon and Glenelg Rivers, west- 
ward of the Grampians, and includes the western terminal spurs 
of the Main Divide ; the other is a tract of country in the north- 
eastern portion of the colony lying to the eastward of the Dividing 
Range between the Ovens and Kiewa Rivers, and of the heads of 
the Durgo River, extending southward of the Main Divide into 
the Tainbo Valley, and eastward and northward to the Murray. 
The rocks of the western area have been but little examined, 
and are very much overlaid by newer deposits ; they occur exposed 
between the Wannon and Glenelg Rivers, north of the former and 
south and east of the latter. They surround a central mass of 
granite, to which their relation has not yet been studied, and con- 
sist principally of brown and white fine to coarse quartzites, some 
curious forms of granulito, folialod micaceous, talcose, chloritic, and 
serpentinous schists, and schists composed of alternating quartzose 
and argillaceous laminae. They are uncouformably overlaid by 
