206 Geology of Sydney. 
the old shore-line, to the north, an extensive volcano 
poured out sheets of lava, and darkened the air with 
volcanic ash. The main coast-line was far out to the 
east. Gradually marine forms of life disappeared, and 
fresh or brackish water took the place of the sea. 
The land continued to subside. Many thousands of 
feet of coal measures were formed in a vast morass, 
covered with vegetation, it is true, but monotonous as 
the Great Dismal Swamp of Carolina. The sea once 
more made inroads. The land was, however, still 
subsiding, and the vast beds of vegetation were buried 
beneath marine clays and sands. 
The Upper Marine Series tells us of a sea with 
fish, swarming with crinoids, crustaceans, and shells. 
Oh the land below Kiama, strange disturbances are in 
progress. The waters are now and again lifted into 
billows, and tidal waves sweep the shores. The noise 
of escaping gases and steam begins to be heard. The 
wild confusion of the hitherto placid sea tells of 
heated lavas and the waters of the deep contending 
for the mastery. At last, the internal fires assert their 
supremacy, and soon volcanic cones stand above the 
waves. Clouds of vapour hang low in the air. Elec- 
trical discharges produce thunders hardly louder than 
the roar from the craters below. Lavas are poured out 
in fiery streams, and tuffs and ash deposits accumulate. 
But the day comes when the fires are cooled, and now 
the ejected volcanic material forms a new and fertile 
soil for a fresh growth of vegetation, which goes to form 
the coal of the coal measures resting on the Kiama 
