16 U.S.C. § 459d-1
The Secretary of the Interior (hereinafter referred to as the "Secretary") is authorized to acquire by donation, purchase with donated or appropriated funds, condemnation, transfer from any Federal agency, exchange, or otherwise, the land, waters, and other property, and improvements thereon and any interest therein, within the areas described in section 459d of this title or which lie within the boundaries of the seashore as established under section 459d-2 of this title (hereinafter referred to as "such area"). Any property, or interest therein, owned by the State of Texas or political subdivision thereof may be acquired only with the concurrence of such owner. Notwithstanding any other provision of law, any Federal property located within such area may, with the concurrence of the agency having custody thereof, be transferred without consideration to the administrative jurisdiction of the Secretary for use by him in carrying out the provisions of sections 459d to 459d-7 of this title.
The Secretary is authorized to pay for any acquisitions which he makes by purchase under sections 459d to 459d-7 of this title their fair market value, as determined by the Secretary, who may in his discretion base his determination on an independent appraisal obtained by him.
In exercising his authority to acquire property by exchange, the Secretary may accept title to any non-Federal property located within such area and convey to the grantor of such property any federally owned property under the jurisdiction of the Secretary within such area. The properties so exchanged shall be approximately equal in fair market value: Provided, That the Secretary may accept cash from or pay cash to the grantor in such an exchange in order to equalize the values of the properties exchanged.
16 U.S.C. § 459d-1
STATUTORY NOTES AND RELATED SUBSIDIARIES
REVISION OF BOUNDARIES; ADDITION AND DELETION OF ACREAGEPub. L. 94-578, title I, §101(13), Oct. 21, 1976, 90 Stat. 2733, as amended Pub. L. 96-199, title I, §111, Mar. 5, 1980, 94 Stat. 70, provided in part that: "The Secretary of the Interior is authorized to revise the boundary of the seashore [Padre Island National Seashore, Texas] to add approximately two hundred and seventy-four acres and to delete approximately two thousand acres, and sections 302 and 303 of the Act of April 11, 1972 (86 Stat. 120, 121) [Pub. L. 92-272 which sections were not classified to the Code], shall apply to the boundary revision authorized herein."