This area was proclaimed as a conservation park in 1976 primarily to conserve its geological features. These features are of worldwide significance, particularly as a record of an ice age about 280 million years ago. Four main periods of geological history in the Hallett Cove area are described on the trailheads at the entrances and along the trails. The park also conserves native flora and fauna.
In 1875, Professor Ralph Tate found the smoothed and striated ‘glacial’ pavement at Black Cliff and was the first person to realise that South Australia had been subjected to an ice age. But which one? The age of the glaciation was debated until in 1895 Professor Walter Howchin suggested that it was of Permian-Carboniferous age, that is about 280 million years old.
Subsequent geological work has demonstrated that at that time Australia was much closer to Antarctica and was part of the ancient land mass called Gondwana. During that time the south-western two-thirds of Australia, including much of South Australia, was covered by an ice cap and glaciers, similar to present day Antarctica.
In 1957, Professor AR Alderman from the University of Adelaide wrote to the National Trust recommending that the excellent glacial pavements along the coastal cliff tops of Hallett Cove be preserved. For the 19 years following this letter, conservationists and community groups fought to preserve these valuable geological sites against suburban development. Finally, in 1976 the park was dedicated for the protection of features of scientific (geological) and historic interest in the Hallett Cove area.