The trees most usual on these tracts, were the box, an unnamed species of eucalyptus, and the grass chiefly of that kind, called the oat or forest grass, which grows in tufts at considerable distances from each other, and which generally affords good pasturage.

On the richer grounds the angophora lanceolata, and the eucalyptus mammifera more frequently point out the quality of the soil on which they grow.

The first are abundant on the alluvial flats of the Nepean, the Hawkesbury and the Hunter; the latter on the limestone formation of Wellington Valley and in the better portions of Argyle; whilst the cupressus calytris seems to occupy sandy ridges with the casuarina.

It was impossible that these broad features should have escaped observation: it was naturally inferred from this, that the trees of New South Wales are gregarious; and in fact they may, in a great measure, be considered so.

The strong line that occasionally separates different species, and the sudden manner in which several species are lost at one point, to re-appear at another more distant, without any visible cause for the break that has taken place, will furnish a number of interesting facts in the botany of New South Wales.
It was observed both on the Macquarie river and the Morumbidgee, that the casuarinae ceased at a particular point.