In the early 1830s he was in private practice in Van Diemen's Land as a surveyor, then moved to New South Wales where he joined the survey department.
Darke brought a wooden caravan from Sydney and set up camp with his family near Robert Russell's wood and daub hut on the south side of the Yarra River in what is now central Melbourne.
[1][2] The caravan, dubbed 'Darke's Ark', had two rooms and a piano, and was drawn by bullocks to locations convenient to his surveying duties around Port Phillip.
[1][2] For a time Darke located his caravan at the seaside in what is now the inner city suburb of Port Melbourne after cutting the first track through the tea tree scrub.
[1] He hoisted a barrel on a pole, on high ground to point the way back to the Melbourne settlement and this led to the area's early name of 'Sandridge'.