Page:Australia, from Port Macquarie to Moreton Bay.djvu/44

 inclination of the declivities of the mountains is twenty-five degrees, nor does it usually exceed thirty-three, at which inclination the beech and spruce grow. The greatest declivities at which ground can be advantageously cultivated have an inclination of thirty degrees." Now I have frequently observed at the MacLeay river, sides of gullies, &c. with an inclination of upwards of fifty degrees, covered with grass and trees; the long roots of the common Australian forest grass may possibly exercise some influence in retaining soil on a rocky surface of so great an inclination, whilst the edges of the almost vertically disposed strata of the schistose formation would occasion a rough surface, along which the soil could not easily slip.

In returning to the mouth of the MacLeay river, and proceeding eleven miles north of it, along the coast, we arrive at the mouth of the Nambucca river, which communicates with the ocean, over a rocky impassable bar. The Nambucca river is formed by several mountain streams, rising in brushy gullies. When these streams have attained a fall low enough to be affected by the tide, they form salt-water inlets, navigable for boats, which all unite in one main channel a short distance from the bar. In my survey of the navigable arms of the Nambucca river, I did not find it possessed of any important features; its banks consisted of mangroves, teatree swamps, dense forest, and cedar brushes. On