In February 1839, he left the Goulburn and steered a course for the Grampian Mountains, where he struck the Wannon, and followed it down to the Glenelg.

Here he came upon one of the Henty stations, and was strongly advised not to persist in his attempt.

Captain Hart, who had been examining the country with the same purpose in view as Bonney's, stated that it would be impossible to take cattle through and turned back with his own to follow the old route round the Murray bend.

But Bonney was not to be daunted, and resolutely pushed on west of the Glenelg.

He discovered and named Lake Hawdon, and also named two mountains, Mount Muirhead and Mount Benson.