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
Toe the line which have lost all evocative power and are merely used because they save people the trouble of inventing phrases for themselves." The expression is used in a Beatles song—"Trying just to make you "toe the line"" in 1965's "Run for Your Life"—and is the basis for Rocky Burnette's 1980 hit song, "Tired of Toein' the Line". Toe the line "Toe the line" is an idiomatic expression meaning either to conform to a rule or standard, or to stand poised at the starting line in a footrace. Other phrases which were once used in the early 1800s and have the same