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
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