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
Lew Wallace position and prevent the enemy from escaping and without Grant's authority to take the offensive. With the Confederates continuing to advance, Wallace led a second brigade to the right and engaged the Confederates with infantry and artillery. Wallace's decision stopped their forward movement and was key in stabilizing a defensive line for the Union troops. After the Confederate assault had been checked, Wallace led a counterattack that regained the lost ground on the Union right. On March 21, 1862, Wallace, McClernand, and C. F. Smith were promoted to major general for their efforts. Wallace, who was age thirty-four at the