108 
Geology and Physical Geography: 
were, as elsewhere throughout the colony, loftier than they aro 
now, and the sea was nearer to their bases. As the laud rose 
after the last Upper Tertiary submergence, the rivers con- 
tinued to erode their courses deeper, cutting through the Older 
Pliocene marine deposits deep into the Silurian bed-rock, their 
courses lengthening and their rate of decline decreasing as their 
sources became lowered by denudation -and as the emergence of 
the land caused the retreat of the seas into which they emptied 
themselves. 
The accompanying table, previously published in the Geological 
Progress Report No. VI., is subjoined, as conveying some idea of 
the operations at work during the Tertiary period in different 
parts of the colony : — 
Table showing Geological operations, probably contemporane- 
ously, in progress in the Ballarat and Gippslaud districts 
• respectively, during the Tertiary epoch : — 
BALLARAT. | GIPPSLAND. 
Lower Tertiary (Eocene and Oligocene). 
Country more deeply depressed below sea-level than at present, and 
-coast-line nearer to the bases of the hilly country. The mountains less 
denuded, and consequently higher than now. Marine deposits in progress 
along coasts. General atmospheric and fluviatile denudation on laud. 
Middle Tertiary (Miocene). 
Marine deposits in progress along coasts. Probable oscillations of land 
surface as regards sea-level. 
Atmospheric and fluviatile action 
on laud as before. Lakes in exist- 
ence in which lignite deposits ac- 
cumulated. Lava-flows of the Older 
Volcanic period took place, but not 
in the immediate neighbourhood of 
Ballarat. 
Atmospheric and fluviatile action 
as before Lakes in existence in 
which lignite deposits accumulated. 
Lava-flows of Older Volcanic took 
place, filling in the greater number, 
if not all, of the valleys and depres- 
sions. 
UprEU Tertiary (Pliocene). 
Lower Pliocene Period. - 
Oscillations of laud surface as regards sea-level, the country being at one 
time depressed by about 900 feet lower than now below sea-level. Marine 
formation in progress along coasts to that elevation above present sea-level. 
Rivers eroding their courses 
deeper than before, cutting through 
previously-deposited gravels, and 
leaving remnants of them on slopes. 
General atmospheric and fluviatile 
action as before ou land surface. 
Towards the close the first lava- 
flows of the Newer Volcanic period 
took place, partly filling in the val- 
leys. 
Fluviatile and atmospheric action 
on land continued. Rivers com- 
mencing to cut new courses along 
and through the Older Volcanic 
lava-flows. 
