In regard to the land grant, the Land Office was called on for a great many decisions after 1864, mostly in interpretation of the exemptions carried in the federal legislation. The cases were not all brought by or against the Central Pacific, but they nevertheless affected its rights. In general, the grant of land to the Central Pacific was held to be an absolute unconditional present grant. The route not being at the time determined, the grant was in the nature of a float, and the title did not attach to any specific sections until they were capable of identification. When once identified, however, the title attached to specific sections as of the date of the grant, except in the case of sections which were specifically reserved.[86] While the grant was a present grant, it conveyed only land which was public land, that is to say, portions of the public domain which were open to sale or other disposition under general laws at the time the grant was made. This definition did not include lands which became public subsequent to the date of the grant, or lands reserved by competent authority for any purpose or in any manner, whether or not the reservations were mentioned in the granting act.[87] It followed from the theory that the land grant was a present grant, that a valid homestead entry existing at the date of the passage of the Land Grant Act excepted the land covered from the area granted to the railroad even though the entry were canceled prior to the definite location of the railroad line.[88] The same effect was produced by an uncanceled and unexpired pre-emption claim, or by any other valid claim or reservation which was alive at the date of approval of the granting act. In cases like these the cancellation of the claim restored the land in question to the public domain, but did not operate to replace it within the railroad grant.[89]