The state of Kansas does herewith and hereby convey all right, title and interest in and to all oil and gas in place, in and under any and all right-of-way, heretofore obtained in the name of the state highway commission of the state of Kansas, by purchase, dedication or condemnation for state highway purposes as authorized by Kan. Stat. Ann. § 68-413, and acquired pursuant to article 1,chapter 26 of the Kansas Statutes Annotated and any amendments thereto, which have not otherwise been disposed of as provided by law, to the present owners of the land of which it was originally a part, save and except a right-of-way easement for highway purposes for all such lands, and an easement right to water, gravel, stone, sand or other material, or to spoil banks or borrow pits, or any bed, pit, quarry or other places where gravel, stone, water or other material may be located, which is now in possession of or has been acquired by the state of Kansas for construction, improvement, reconstruction, maintenance, or drainage of the state highway: Provided, however, That where the state of Kansas or the state highway commission has heretofore acquired title to real estate by warranty deed for any highway purpose or by purchase, dedication or condemnation for sites for the construction of buildings or any improvement thereon necessarily incident to the operation, maintenance and supervision of a system of state highways, the fee simple title, from and after the effective date of this act, shall be and remain vested in the state of Kansas.