British naturalist Alfred Russel Wallace described a dividing line (Wallace Line) between the distribution of Indonesia's Asian and Australasian species. It runs roughly north–south along the edge of the Sunda Shelf, between Kalimantan and Sulawesi, and along the deep Lombok Strait, between Lombok and Bali. Flora and fauna on the west of the line are generally Asian, while east from Lombok, they are increasingly Australian until the tipping point at the Weber Line. In his 1869 book, ''The Malay Archipelago'', Wallace described numerous species unique to the area. The region of islands between his line and New Guinea is now termed Wallacea.