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
Line of purples absent from the gamut of sRGB. Magenta ink, which is one of CMYK's primaries, is also very distant from the Line for the reason explained above. The wide-gamut RGB color space approximates the colors on the Line better, but devices capable of displaying colors with this enhanced system are prohibitively expensive for ordinary consumers. Most of the names of the purple colors in the table below do not denominate colors on the line of purples, but instead are slightly less than maximally colorful, i. e. saturated. Line of purples In color theory, the line of purples or purple boundary is