This thesis is an attempt to reconstruct the physical environment of the Port Phillip area as it was at the time of first European arrival, ie. c.1800. At the time it was first encountered by Europeans, in 1803, the land around Port Phillip Bay supported a wide diversity of ecosystems. For millennia the area was the territory of Aboriginal clans belonging to two language groups, Woi wurrung and Boon wurrung. These peoples lived in spiritual union with the land, exploiting its abundant resources, and, through a range of practices, maintaining it in the form in which it had been created. The encroachment of Europeans onto clan estates, beginning in the 1830s, brought dramatic changes to this Aboriginal way of life, and also to the local landscapes themselves. The thesis propounded here is that the natural history of the area was a major influence on the occupation and use of the area by humans, and that to understand the particulars of that natural history is to have an insight into the human history. The bulk of the study is therefore a reconstruction of that natural history, which is offered as the physical context of human action in the area. (For complete abstract open document)