Wallace Line to the west of the Philippines. Wallace's studies in Indonesia demonstrated the emerging theory of evolution, at about the same time as Joseph Dalton Hooker and Asa Gray published essays also supporting Darwin's hypothesis. Understanding of the biogeography of the region centers on the relationship of ancient sea levels to the continental shelves. Wallace's Line is visible geographically when the continental shelf contours are examined; it can be seen as a deep-water channel that marks the southeastern edge of the Sunda Shelf which links Borneo, Bali, Java, and Sumatra underwater to the mainland of southeastern Asia. Australia is likewise connected
Collins–Valentine line Collins–Valentine line The Collins–Valentine line, or Valentine–Collins line, is the boundary at approximately 45 degrees north latitude that separates the province of Quebec from the states of New York and Vermont. It was surveyed and marked by survey monuments in 1771–3 by John Collins, surveyor-general of Quebec, and Thomas Valentine, a commissioner appointed by the government of New York. Quebec had been a French colony until the conclusion of the Seven Years' War in 1763, when it became a British colony. In the 1760s, the region that would later become a state of Vermont was considered by authorities in Britain