1128 The Geology of Central Australia. {November 
slow oscillation and general quiet, during which beds of sediment 
were formed slowly at the bottom of the sea. At the close of the 
Paleozoic the eastern border and perhaps the western was ele- 
vated, thus forming an interior sea and foreshadowing the form 
of the continent. Another period of repose then followed until 
at the close of the Jurassic a large disturbance occurred. Land 
slowly emerged from the central part of the sea around the island 
of Archzan rocks now known as the Peake range. Contempo- 
raneously with this upheaval vast floods of felsite were poured 
out through a line of fracture trending north and south on the 
western boundary of this region of elevation. Then came another 
period of rest, during which the waves and currents of a Creta- 
ceous sea worked away at these new rocks. On the west side 
vast beds of kaolin were formed, derived from the felsitic rocks. 
In the remainder of the sea the conditions were much the same 
as in the Jurassic period, and similar beds were formed. But the 
fauna shows a gradual change in the life dwelling in the seas, # 
might be expected. _ | 
Finally, at the end of the Mesozoic age, the whole of the inte- 
rior basin was elevated above the sea, and though minor changes 
of level have occurred, has remained above ever since. Dae | 
all these changes of level the southern portion of the continent 
had not yet appeared, except the southern extremity of the F i 
der’s range. But since the Miocene period the southern patt iy 
the continent was raised above the sea. Either cone : 
ously or subsequently there was a large amount of volcanic ie : 
turbance. After this there was a subsidence, as is see? si - 
fringe of zolian sandstones which, for a short distance out yea 
surrounds the southern coast. at : 
During Tertiary times there was a subsidence along por 
ern border. According to Tenison-Woods there 1$ a long * i 
at the edge of the Blue mountains, and for many miles ™ ae 
bury = 
stone (Mesozoic) nearly to the level of the sea, 
the fiords and diversified scenery of Port Jackson and 0 
of the eastern coast. The existence of the Great Barri 
dicates a period of slow subsidence on the north-eas 
Tertiary times, The western coast seems to have “aie e 
pated in the general upheaval at the close of the ee has 
raised beaches have been noticed there. The interior © 
