Wallace Line genus of plants which does not cross the Line is the Australasian genus "Eucalyptus". Antonio Pigafetta had recorded the biological contrasts between the Philippines and the Maluku Islands (Spice Islands) (on opposite sides of the line) in 1521 during the continuation of the voyage of Ferdinand Magellan, after Magellan had been killed on Mactan. Moreover, as noted by Wallace himself, the observations in faunal differences between the two regions had already been made earlier by English navigator George Windsor Earl. In Earl's pamphlet "On the Physical Geography of South-Eastern Asia and Australia", published in 1845, he described how shallow seas
Sunda Shelf these areas of the Asian continental shelf that were exposed during the last ice age. Sundaland included the Malay Peninsula on the Asian mainland, as well as the large islands of Borneo, Java, and Sumatra and their surrounding islands. The same steep undersea gradients that mark the eastern boundary of Sundaland are identified biogeographically by the Wallace Line, identified by Alfred Russel Wallace, which marks the eastern boundary of Asia's land mammal fauna, and is the boundary of the Indomalaya and Australasia ecozones. The shelf has resulted from millennia of volcanic activity and erosion of the Asian continental mass, and