1870.] DUNCAN—AUSTRALIAN CORALS, 287 
the upper parts of the series, is rare ; it contains there an abundance 
of Polyzoa, and is a deep-sea deposit. It would appear that this lime- 
stone, so well displayed under the basalt of Mount Gambier, to the 
west of the south-western boundary of Victoria, is better developed 
where it is most remote from the high Paleozoic land, in Central 
Victoria, and that its position in the tertiary scale is occupied, near to 
that origin of muddy and sandy sediments, by clays containing more 
or less of the latter. The upper series of Mount Gambier, called by 
the Rev. Mr. Woods the “ Coralline crag,’ may be recognized at 
Cape Otway and in Mr. Daintree’s section. In both of these locali- 
ties the limestone, which closely resembles the white chalk at Mount 
Gambier, is impure and very much mixed with sediment and some 
volcanic ash. Other limestones are found low down in the fossili- 
ferous series, and often form masses like islands in a mass of basalt ; 
but I have not had any fossils from them. 
The most fossiliferous parts of the series are yellow and brown 
ferruginous clays, and dark slate-coloured bands more or less sandy. 
In the Cape-Otway series there is a plant-bed containing ever- 
green leaves, of species not belonging to the existing flora; it is 
sufficiently developed to lead to the belief that a temporary up- 
heaval must have occurred, followed by a long subsidence. The 
deposits which collected during this subsidence resemble those of 
the upper part of every section of the Tertiaries. They bear wit- 
ness to the action of currents, to the influx of mud and sand, lava, 
and volcanic ash, and prove not only that voleanic phenomena were 
very active close by, but that the older rocks which formed the 
shore to the north-east were suffering tremendous denudation. 
Vast developments of clays with fossil leaves, gravels, and con- 
glomerates were proceeding on the area of the Silurian rocks, 
which formed the shore and land washed by the tertiary sea, whilst 
the marine deposits were forming. Even at the altitude of 4000 
feet water-worn gravels and boulders were collecting, in some places 
to the depth of 300 feet. This old gravel, resting on the worn 
surfaces of the Silurian rocks, is covered in many places by a basalt, 
whose representative is low down in the marine series on the coast 
and frequently forms its base. 
An immense district, extending from Port Phillip to the river 
Glenelg, is covered with a basalt which is younger than that just 
mentioned. It was poured forth over the clays and marls of which 
the Hamilton beds are the type; and it covered the littoral and 
moderately deep-sea deposits which were in-shore of the deep sea, 
forming the chalky sediment. Mr. Woods has described its position 
in relation to the fossiliferous beds of Hamilton. Still later, and 
when these deep-sea deposits had crept over much of the subsiding 
in-shore series, which had or had not been covered with the basalt, 
another and long -continued lava-stream, accompanied by ash, 
poured from the Mount-Gambier district and many of the formerly 
active vents in Victoria. It covered up the coralline rocks, as they 
are called, and mixed with and included the lacustrine and river- 
sediments then forming; and it probably continued to flow until 
