OF THE INTERIOR OF WESTERN AUSTRALIA. 173 
red, while gum-trees are the most prominent element in the 
vegetation—it is, in short, an auriferous zone. But no sooner 
is the salt lake at Goongurrie crossed, than an entire change 
takes place in the vegetation. From this point onward gum- 
trees are few in number, and for the most part restricted to the 
banks of creeks, and their place is taken by * Mulga” (Acacia), 
by Eremophilas, Proteacez, Casuarinas, &e. The general hue 
of this vegetation is a dark olive-green, and this renders the 
scene dreary to a degree. "There is, however, one alleviation, 
inasmuch as the bright green foliage of that beautiful tree, the 
Currajong (Sterculia diversifolia, G. Don), rare and seldom seen 
further west, often refreshes the traveller's eye in this back 
country. Goongarrie is situated close to the thirtieth parallel of 
South latitude; and as the change in the vegetation is here so 
abrupt, I have, as will afterwards be shown in more detail, 
assumed this parallel as marking the division between two floras. 
Whether the line should run due east and west is a moot point 
—its trend is probably north-west or north-north-west. I find, 
however, by proceeding on the just-mentioned assumption and 
comparing all available records, a considerable percentage of the 
plants found to the south of the thirticth parallel are different, 
specifically or generically—generally the former—from those 
having their habitat north of it. The primary difference between the 
two regions, the rarity of gum-trees in the one and their abundance 
in the other, is a fact well known to mining men, one of the most 
serious drawbacks to mining enterprise in the northern districts 
being the scarcity of suitable timber, while its abundance south 
of the thirtieth parallel, as at Southern Cross, Coolgardie, 
Kalgoorlie, and other centres, is a fact well known to all *. 
From Mount Margaret a short expedition was made to “ the 
table-topped mountain,” a low elevation a few miles to the north- 
east, which has by some, appareutly in error, been identified 
with the hill called by Sir John Forrest, Mount Weld. The 
camp was then fixed at the Hawk’s Nest, situated at the foot of a 
diorite range of low elevation, the scene of a then almost deserted 
* This difference between the nearer and more distant parts of the desert 
was first brought to my notice by Sir John Forrest in an interview I had with 
him before leaving for the Interior. I mention this for the purpose of empha- 
sizing a fact which had evidently impressed itself deeply, during the early 
pioneering days when he first won his spurs, upon the mind of a man who 
himself makes no special claim to being a botanist. 
02 
