The cycads may have become stranded in Central Australia during the Late Jurassic or Early Cretaceous about 125–140 million years ago, as the break-up of Gondwana was accompanied by a cooling period, then a warming period, and sea levels rose and inundated vast areas of inland Australia (White, 1986). They are relicts from a time when warm and humid conditions supported a luxuriant vegetation of cycads, conifers, and ferns throughout Australia, and when even adjacent Antarctica had conifers and cycads. See Memories of Gondwana—The Palms of Palm Valley