4 
INAUGURAL ADDRESS. 
Gympie rocks as Permo-Carboniferous, there was no important altera- 
tion in the geographical limits during the Devonian period, or in the 
earlier Permo-Carboniferous Gympie beds, but shortly after this there 
were very decided variations in both the area and altitude of the land. 
The whole of the present continental area was raised sufficiently to 
lift large portions of the previous sea bottom above its surface. The 
principal elevation was on the eastern coast, where the rise must have 
been several thousand feet, while on the west it was less pronounced, 
though the area added to the land appears to have included nearly the 
whole of what is now Western Australia. In regard to the inter- 
vening space between it and the eastern ranges, there is only the 
negative evidence of no later marine deposits to indicate that it also 
was above the ocean. Although the general elevation of the continent 
appears to have been quiescent in the western and central parts, there 
were violent disruptions on the eastern coast, and the strata were 
apparently crushed by a force from the east, which lifted them into a 
series of waves, showing the faces of dislocation to the east and strata 
sloping to the west, the most easterly wave being near the present 
coast-line, and the succeeding waves more gradual as they recede to 
the west, both in angle and height, until they merge into the level of 
central Australia. It is also probable that the South Australian range 
was also the result of this compression, causing the strata to rise in 
abrupt masses on an axis nearly north and south. Tt was at this stage 
of disruption and elevation of strata that the more important auri- 
ferous deposits of both the eastern and western parts of the continent 
were formed, and these maybe divided into two classes:- — (1) True 
fissure veins, or lodes, in which the deposits of ore are found filling 
fissures in the slate strata, and which are generally nearly vertical ; 
and (2) floors of ore which occur in sheets dipping at a less angle from 
the horizontal than the vertical, the including rock being of crystalline 
character, being, in fact, intrusive granites. The dip of these sheets 
of ore is in the direction of the huge dykes of intrusive rock in which 
they occur. 
AURIFEROUS DEPOSITS IN LODES. 
There was not only great disruption of the strata, but igneous 
rocks forced themselves into the fissures in the sedimentary beds, and 
the resulting metamorphism of the adjacent rocks increased the 
confusion, as beds of slate may be traced through the transformation 
of their sedimentary character, by the recrystallisation of their 
component elements into diorites, having that peculiar structure of 
radiating crystals which usually characterises rocks of volcanic origin. 
As regards the auriferous deposits in these lodes, it appears that first 
simple fissures were filled with water from the ocean or deep-seated 
sources ; but in either case the powerful electric currents which 
continually traverse the earth’s surface east and west met resistance 
at the lines of disruption, and electric action being developed the 
