Wallace Line by the Sahul Shelf to New Guinea. The biogeographic boundary known as Lydekker's Line, which separates the eastern edge of Wallacea from the Australian region, has a similar origin to the Wallace line. During ice age glacial advances, when the , both Asia and Australia were united with what are now islands on their respective continental shelves as continuous land masses, but the deep water between those two large continental shelf areas was, for over 50 million years, a barrier that kept the flora and fauna of Australia separated from those of Asia. Wallacea consists of islands that were not
Define the Great Line 200 since 1997. The title of the album, according to keyboardist Christopher Dudley, comes from "defining that line for yourself between becoming the man or the woman that you want to be and the man or the woman other people want you to be." "Alternative Press" used the title as an example of how on this album Underoath seemed "acutely aware of the line that separates their spiritual core from the painful reality of being human," and how "even successful musicians need help staying on the right side of that line." Unlike "They're Only Chasing Safety", "Define the Great Line"