comprising approximately 7,591 acres, identified as O'Neil Creek on the Map, which shall be known as the O'Neil Creek Wilderness . (BBBBB) Bridger range wilderness Certain Federal land within the Custer-Gallatin National Forest comprising approximately 54,046 acres, identified as Bridger Range on the Map, which shall be known as the Bridger Range Wilderness . (CCCCC) Beartooth mountain wilderness Certain public land administered by the Lewistown Field Office of the Bureau of Land Management comprising approximately 6,517 acres, identified as Beartooth Mountain on the Map, which shall be known as the Beartooth Mountain Wilderness . 109. Administration (a) In general Subject to valid existing rights, land designated as wilderness by this title shall be administered by the Secretary concerned in accordance with the Wilderness Act ( 16 U.S.C. 1131 et seq. ), except that— (1) any reference in that Act to the effective date shall be deemed to be a reference to the date of the enactment of this Act