84 THE ORIGIN OF AUSTRALIA 
DESCRIPTION OF PLATES. 
Pratz VI..-GEOLOGICAL. 
In this plate the Cretaceous Beds are shown as exposed at the surface. 
They certainly underlie some of the dotted areas, and part of the Western 
Australian area marked Tertiary. How much of the sandy material of the 
Northern Territory and West Australia is of Tertiary age is not yet certain. 
The object of this map is simply to show how completely the Mesozoic and 
Tertiary Rocks cut the continent in two. 
Puate VII.\|PRE-CRETACEOUS AUSTRALIA. 
This map is founded on Plate I, and shows the geographical conditions 
which must have obtained prior to the infilling and upheaval of the Opal 
Sea-bed. The coast line should have been continued to include Tasmania. 
The coast of Australia-Orientalis most certainly extended further eastwaid 
than shown, and that of Australia-Vera further westward, but I have con- 
fined the outline to the present limit of the Continent. 
Prats VIII.—BOTANICAL. 
This plate illustrates how completely isolated are the floras of the East 
and West, and how comparatively poor the central region is. The Prote- 
ace were selected because they are a typical order of Australian plants, 
rich in genera and species, and not because they illustrate my theory better 
than other orders, or than the flora as a whole would do. Indeed the 
entire flora emphasises the peculiarity much more strongly than does any 
particular order of plants. 
I have not made any scientific division of the continent, but if such 
divisions as those suggested by Prof. Baldwin Spencer were used, the facts 
would come out much more strongly. His Torresian largeiy coincides with 
my Orientalis, but he carries it along the Gulf coast, which belongs to the 
most recent instead of the most ancient part of Australia. This part of the 
Torresian area is characterised by true Asiatic species of plants—derived 
indeed from Asia. 
The division of the Australian flora into Tropical and Extra-tropical, 
though real, obscures the facts of the origin of the plants. The Asiatic 
plants are all tropical, but then so are many of the true Australian plants, 
and the richness and wide-spread extent of the extra-tropical flora is simply 
due to the fact that in Tertiary times the only tropical habitat was in the 
northern portion of the narrow land of Australia Orientalis, while the 
greater part of Australia Vera, and the southern part of A-Orientalis (in- 
cluding Prof. Spencer’s Bassian) was geographically extra-tropical and far 
wider in extent. 
