388 PHYSICAL STEUCTURE AXD GEOLOaT OF ArSTEALIA, 



Calcareous Sandstones which for a short distance out to sea, 

 surrounds the south coast. There has then been over a limited 

 area on the south-east side of the Continent a renewal of volcanic 

 activity and slight elevation of the coast. On the east side there 

 is no evidence of upheaval for its whole extent, but there are 

 very decided marks of subsidence in, probably, tertiary times. A 

 long fault occurs at the edge of the Blue Mountains near Penrith, 

 and for many miles north and south, there is a down- throw which 

 brings the Hawkesbury Sandstone nearly to the level of the sea, 

 when it forms the romantic castellated fiords and diversified 

 scenery of Port Jackson, Broken Bay, &c. The existence of the 

 Barrier Beef on the north-east coast is also generally regarded 

 as marking a slow period of subsidence. This view is confirmed 

 by the general conformation of the coast line, mountain system, 

 and islands. The subsidence must have been in tertiary times, 

 because the recent alluvial drifts are disturbed by it. 



The upheaval of the coast line of the Australian Bight must 

 have been of a very rapid character, Priable limestone cliffs, 

 600 feet high, abut upon the sea. Had there been any pause, 

 even of a few months, in the uplifting, there must have been some 

 traces left by erosion, but no such marks are found. It might 

 be an interesting speculation to inquire if the subsidence on the 

 east coast was a compensating phenomenon for the upheaval on 

 the south, since the extent is about the same. The phenomena 

 represented are at any rate out of even extraordinary terrestrial 

 experience. The west coast seems also to have participated in 

 the upheaval. Shells of a recent age were forwarded to mc from 

 Premantle, which showed the existence of raised beaches. The 

 only difference between the marine fauna and that at present 

 existing was that it included tropical species only now found in 

 North A^ustralia. 



As to the epoch to which the oldest dry land in Australia may 

 be referred there are no very certain data. The fauna and flora 

 would incline us to believe that we have relics of the later 



