Amends the Act of June 25, 1910 (36 Stat. 847) to make the lands withdrawn open to mining of "metalliferous minerals," and adds California to the list of states within which new or additional forest reserve lands (national forests) are forbidden.
36 Stat. 847 had authorized the President to withdraw public lands from entry for specified purposes. See also the portion of the Agricultural Appropriations Act passed in 1907 which forbids Presidential withdrawal of lands for forestry purposes in specified states (34 Stat. 1269).