The authority given the Land Department over surveys of "public lands" of the United States, and its authority under the preemption law to patent lands "belonging to the United States," did not empower it to make a survey defining the boundary between an upland lot belonging to the United States, and tideland belonging to a State, which would be conclusive against the State or her grantee in a subsequent suit against one claiming the lot under a preemption patent. Knight v. United States Land Assn., 142 U.S. 160, distinguished. P. 16. 5.