Lieutenant John Oxley went down the Lachlan (1817) during one of these periods of flood, and the great plains appeared to him to be the fringe of a vast inland sea.
Taking the Lachlan as one type of Australian river, we find it takes its rise amongst the precipitous and almost unexplored valleys of the Great Dividing Range.
Some small expeditions were made from Bathurst, resulting in the discovery of the Lachlan, and in 1816 the first of the great exploration expeditions of Australia was fitted out under Lieutenant Oxley, R.N.
By Mr Evans and Mr Allan Cunningham the botanist, and the object of his expedition was to trace the course of the Lachlan in a westerly direction.
Oxley traced the river until it lost itself in the swamps east of 147° E., then crossing the river he traversed the country between the Lachlan and Murrumbidgee as far as 34° S.
On his return journey Oxley again crossed the Lachlan about 160 m., measured along the river, below the point where he left it on his journey south.