History of the Yosemite area the Yosemite area in 1863. Pressure from Starr King and Olmsted, photographs by Carleton Watkins, and geological data from the 1863 Geological Survey of California prompted legislators to take action. Senator John Conness of California introduced a park bill in 1864 to the United States Senate to cede Yosemite Valley and the Mariposa Grove of Big Trees to California. The bill easily passed both houses of the United States Congress, and was signed by President Abraham Lincoln on June 30, 1864. The Yosemite Grant, as it was called, was given to California as a state park for "public use, resort
Yosemite National Park alpine glaciers, bucking established scientists such as Josiah Whitney, who regarded Muir as an amateur. Muir wrote scientific papers on the area's biology. Landscape architect Frederick Law Olmsted emphasized the importance of conservation of Yosemite Valley. Overgrazing of meadows (especially by sheep), logging of giant sequoia, and other damage caused Muir to become an advocate for further protection. Muir convinced prominent guests of the importance of putting the area under federal protection; one such guest was Robert Underwood Johnson, editor of "Century Magazine". Muir and Johnson lobbied Congress for the Act that created Yosemite National Park on October 1, 1890.