46 
Geology op Sydney. 
the different periods and which are preserved for ns 
as fossils. Fossil plants are indicative of dry land. 
Stratified rocks containing marine fossils were un- 
doubtedly formed in the sea. Other fossils point 
conclusively to the fact that the rocks containing 
them were laid down in fresh water. 
Summed up, fossils are evidences of life in times 
gone by. By their aid we construct the divisions of 
geological time, and they tell us of the conditions 
under which rocks were deposited. 
“ The existence of fossil remains is, then, a fact. 
Go where you will through the civilized world, and 
every chief town has its museum, into which they 
have been gathered by the zeal and industry of man ; 
descend where you can into the crust of the earth — 
the quarry, the mine, the railway cutting — and there, 
notwithstanding the plunder which has been going 
on for two centuries and more, you will find that the 
inexhaustible cabinets of Nature are still teeming 
with these remains of ancient life. 
“ When we are brought, for the first time, face to 
face with these countless relics of a former world, we 
are impressed with a sense of wonder and bewilderment. 
That the skeletons before us, though now dry and 
withered, were once animated with the breath of life ; 
that the trees now lying shattered and prostrate and 
shorn of their branches, once flourished on the earth, 
we cannot for a moment hesitate to believe. But, 
beyond this one fact, all is darkness and mystery. 
