Exclusive jurisdiction be, and the same is hereby ceded to the United States over the tract of land comprised within the cemetery known as the Fort Gibson National Cemetery, area about nine (9) acres in Muskogee County; provided, however, that the State of Oklahoma reserves the right to serve civil or criminal process within said cemetery reservation in suits or prosecutions for or on account of rights acquired, obligations incurred, or crimes committed in said state but outside of said cemetery reservation.