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
Brünig-Napf-Reuss line Brünig-Napf-Reuss line The Brünig-Napf-Reuss line forms a geographical boundary in traditional Swiss culture (""). Running from the Brünig Pass along the Napf region to the Reuss (which joins the Aare at Brugg), it partly separates western (Bernese German) and eastern (Zurich German) varieties of High Alemannic, although some places east of the line belong to the western dialect group (Schwyz, Zug). The line runs across the cantons of Lucerne and Aargau. The concept was first proposed by Richard Weiss in 1947, and it reflects the cultural situation in Switzerland as established by ethnographic field work during the early 20th century.