The Secretary of the Interior is authorized to inclose the Sullys Hill National Game Preserve ¹ with a good and substantial fence, to construct thereon all sheds, buildings, and corrals necessary for the proper care and maintenance of the animals and birds therein, to erect a suitable headquarters, to construct and maintain roads, trails, and other structures necessary for the convenience of visitors, and to incur such other expenses as may be necessary for the proper maintenance of the preserve and the animals and birds placed therein. He is also authorized to place in the park buffalos, elk, deer, and such other wild or rare animals and birds as he may in his discretion decide.