Sec. 1. All or any part of the Public Lands belonging to the State situated in and under the bed of Caddo Lake and the tributaries thereto and all or any part of such lands adjacent thereto shall be subject to lease for mineral development by the Commissioner of the General Land Office to any person, firm or corporation in accordance with the provisions of existing or future laws pertaining to the leasing and development of all islands, salt-water lakes, bays, inlets, marshes and reefs, owned by the State within tidewater limits, and that portion of the Gulf of Mexico within the jurisdiction of Texas, and all unsold public free school land, both surveyed and unsurveyed, in so far as same are not in conflict herewith.