To enable the several States (but not including the States of Kansas, Nebraska, and Nevada) to construct the necessary levees and drains, to reclaim the swamp and overflowed lands therein—the whole of the swamp and overflowed lands, made unfit thereby for cultivation, and remaining unsold on or after the 28th day of September, A.D. 1850, are granted and belong to the several States respectively, in which said lands are situated: Provided, however, That said grant of swamp and overflowed lands, as to the States of California, Minnesota, and Oregon, is subject to the limitations, restrictions and conditions hereinafter named and specified in this chapter, as applicable to said three last-named States respectively.