On the 3rd they reached a gentle stony ascent, which proved to be the watershed between the two rivers.

Descending the slope to the northward, they soon came to the head of a watercourse flowing northwards.

They followed the new creek, and on the 6th of May came to a river joining it from the eastward, which at last proved to be the Gascoyne.
Gregory kept down the south bank of the Gascoyne, and on the 12th of May passed a large tributary coming from the north, which he named the Lyons.
On the 17th they ascended a sandy ridge about sixty feet in height, and had a view of Shark's Bay.
He returned along the north bank of the river, and having reached the Lyons, followed that river up.

On the 3rd of June he ascended the highest mountain yet discovered in Western Australia, which he named Mount Augustus, after his brother.

Gregory gives the elevation at 3,480 feet, but Mount Bruce in the Hammersley Range, to the north of it, has since been found to be higher.* From the summit, however, he had an extensive view, and was enabled to sketch in the courses of the various rivers for over twenty miles.
*[Footnote.] 3,800 feet.
As they had now been out 51 days, and their supply of provisions was approaching the end, the party turned back at Mount Augustus, and struck southwards.