43 C.F.R. § 2091.4-3

(a) For lands covered by a Carey Act grant, publication of a notice in the Federal Register that a contract has been signed segregates the lands described in the contract, as of the date of publication of a 10 year period, from operation of the public land laws and the mineral laws as described in the notice. (See part 2610).

(b) If the contract under the Carey Act is terminated, the lands are opened by publication in the Federal Register of an opening order which specifies the date and time of opening. Preference right of entry to Carey Act entrymen may be provided in accordance with the provisions of subpart 2613 of this title.