96 Lectures on the Geology, Botany, fyc., of the 
rather lead us to expect a greater precipitation of moisture round 
its elevated points. 
My observations on the uninhabited parts of the colony, show 
that this desication is not dependent upon colonisation, upon the 
clearing of the ground, and the increase of stock, though there is 
no doubt that the latter must make a great impression on limited 
water-holes not supplied by springs. We are, therefore, com¬ 
pelled to look for the cause in some until now unknown change 
of the atmosphere, which may be periodical, and allow us to hope 
that the continent will be again favoured with a series of more 
rainy seasons. 
Lecture II. 
I shall now give you an account of the change of vegetation we 
experienced in advancing into the tropics. I shall enumerate all 
the edible vegetable substances we found, the change of animals, 
and shall conclude with some observations on the natives we met 
during our journey. 
The vegetation changed very little along the east coast from 
Moreton Bay to the northward. The open forest was generally 
formed by the narrow-leaved and silver-leaved iron-bark; the flats 
were covered by box ; the bergs along the rivers and creeks by 
bloodwood and Moreton Bay ash ; and the immediate banks of 
the creeks were lined by flooded gums and casuarinas, which, 
farther northward, gave way to the drooping tea-tree. We never 
met with vine and cedar brushes like those which grow along the 
rivers of Port Macquarie and Moreton Bay, or on the sides of 
mountains, like the bunya-bunya brushes. There were narrow 
belts of palm-tree brush at the Mitchell, and of bamboo brush on 
the South Alligator River, but nothing to be compared with the 
dense masses of vegetation which are found in the districts above 
mentioned. No species of araucaria was seen; but calitris, the 
cyprus-pine, covers the whole continent wherever a sandy rocky 
soil favoured its growth. The drooping myall ceased at Peak 
Range, the bricklow at the heads of the Burdekin and the Upper 
Lynd, where also the iron-bark disappeared. Several species of 
