116 SUNKLANDS OF PORT PHILLIP BAY AND BASS STRAIT 
exclusively southern climates, the second by tree ferns, sassafras, 
and other forms. 
The floor of Bass Strait between the Bassian and King Island 
ridges suggests a peneplain. After it had been exposed to aerial 
conditions during the lowering of sea level in the glacial stages, 
much of it probably became a dune surface; it owes its slightly 
undulating surface to the flattening effect of wave action during 
the succeeding eustatic rise of sea level. Daly (1934) estimated 
that sea level was lowered 295 feet during the last glacial stage, 
and this uncovered most of the floor of Bass Strait. It exposed 
two types of sea-bottom — an inshore one, the dune surface of the 
Nepean Bay Bar extending 13 miles seawards from the southern 
shore of the Nepean Peninsula and of a total width of more than 
15 miles, and an offshore sea-bottom to the south of this, the gently 
undulating surface of the Tamar Major Kiver basin on which the 
Nepean Bay Bar was built up. During the glacial stages— the 
Yolande or Riss (in part), and the Margaret or Wurm 1, 2 and 3, 
there were presumably four land bridges — partly or completely 
uncovered sea-bottoms of these two types. The Nepean Peninsula 
up to the advent of the white settler had a representative 
marsupial fauna. Marsupial remains have also been found in the 
dune rock, some of extinct species, and it can be inferred that the 
psammiferous flora now on the Peninsula persisted during dune- 
building periods of the glacial stages. This flora is calciphilous, 
a characteristic to be expected from the limestone surface, but it 
owes its presence to the open texture, aeration, and low water- 
holding capacity of the surface. Mr. J. H. Willis, Botanist of the 
National Herbarium, has kindly supplied me with the following 
list and facts concerning species from near Sorrento, obtained by 
him in January; the list may be taken as representative of the 
limestone area. 
Sjnnifex hirsutus Lab., also King Is. and Tasmania. 
Distichlis distichc'phylla (Lab.) Fasset. 
Poa poaeformis (Lab.) Druce, also King Island and Tasmania. 
Agroxtis avenacea Gmelin. 
‘lA. BiUardieri R.Br., also King Is. and Tasmania. 
Stipa teretifoha Steud., also King Is. and Tasmania. 
Sc.irpns nodoxus Rott., also King Is. and Tasmania. 
Casuarina stricta Ait., King Is. and Tasmania. 
Muehlenheckia adpressa Meisn, also King Is. and Tasmania. 
Rhagodia baccaia Moq., also King Is. and Tasmania. 
Atriplex cinereum Poir., also King Is. and Tasmania. 
Disphyma (Mesembryanthemum) australe (Sol.) Black, also King Is. and 
Tasmania. 
Carpobrotus (Mesembryanthermim) aegudaterus (How.) King Is., also Tas- 
mania. 
