TRANSACTIONS OF SECTION E. 443 
porum platycarpum and Hremophila longifolia) and a great variety of shrubs 
(Heterodendron, Fusanus, Pittosporum, acacias, &c.), forming probably the most 
park-like country in Australia. The so-called spinifex, Z'riodia irritans, the 
porcupine-grass of the settlers, prevails throughout. Salt-bush plains comprising 
a large number of the Chenopodiacew vary from a few to many thousand acres. 
Grasses are of the tufty, tussocky order, and rarely form a sod or sole of grass 
sufficient to prevent sand-drift. . 
Climate.—The Mallee is arid. Its rainfall varies from 19 to a little under 
11 inches per annum, averaging 14 inches. In summer the days are intensely 
hot and the air excessively dry ; consequently there is frequently a considerable 
drop in temperature at night-time, the range being over 70° F. In winter, the 
days are bright and sunny with much frost at night, temperatures going com- 
monly below 20° F. Cyclones of destructive force are rare. 
Geology.—The surface soils are almost wholly xolian or wind-redistributed ; 
this formation extends to 30 feet and over in depth. They have been formed 
from lacustrine clays and drifts, which are some 200 feet in thickness. Below 
these beds, enclosed above and below by estuarial blue clays containing broken 
shells, foraminifera, glauconite, &c., are extensive marine formations, poly- 
zoal and shell rocks of about the same thickness as the overlying lacustrine 
beds. Below these are terrestrial fluviatile deposits containing much lignite and 
pyrites. The thickness of these, which rest upon paleozoic, silurian, or granite 
beds, is variable, reaching 700 feet. ‘The sequence of beds shows in the Tertiary 
period a considerable subsidence followed by elevation. While the elevation 
was in progress and the sea had retreated, the streams at present joining the 
Murray River flowed in and formed the lacustrine deposits until, uniting forces, 
they cut a canyon through them to the sea. The Murray River canyon has a 
depth of 60 to 200 feet, and a width of 14 to 4 miles. A distinct folding in the 
whole series of Tertiary beds has been shown by the borings. At the surface 
these folds are many miles in width and are over 200 feet in height and have 
a direction a little west of north—at right angles to the sand-ridges—with a 
marked easterly dip. It is not unlikely that the salt and gypsum areas above 
referred to mark the synclines, where fracturing allows escape of the artesian 
waters of the coral marine beds. 
Settlement.—There are at present five and a half million acres under settle- 
ment, of which about one and a half million acres are under cultivation annually, 
supporting a population of over 40,000. 
3. The Experimental Demonstration of the Curvature of the Marth’s 
Surface. By H. Yuue Oupuam, M.A. 
4. The Central Highlands and ‘ Main Divide’ of Victoria. 
Bytes “Haar MAL BOL. FIGS: 
A belt of highlands extends through almost the whole length of Victoria. 
These consist of a peneplain carved out of Palwozoic rocks, and subsequently 
elevated in blocks to varying heights and dissected. Remnants of older hills 
above the peneplain are of minor importance. 
On these Paleozoic rocks rest fluviatile and lacustrine deposits of Tertiary 
age. The fossils and relation to marine Tertiaries further south indicate a 
position low in the Tertiaries for the oldest of these. The formation of the 
peneplain may be regarded as early Tertiary. In Southern Victoria worn down 
Jurassic rocks form part of the peneplain. On the Central Highlands and south- 
of them there are also two series of volcanic rocks, known respectively as the 
older volcanic (early Tertiary) and newer volcanic (late Tertiary). 
The central belt of highlands is outside the limits of the Jurassic coal- 
bearing sediments and of the marine Tertiaries. This area has been relatively 
high from Jurassic time onward, and has been much more elevated in Tertiary 
times than the marine Tertiary area. 
The general effect produced by the elevation has been a broad belt of high- 
lands falling away to north and south and higher at the eastern end. In detail 
