Oregon Revised Statutes Cities § 226.630

(a) If all of the remains that can be located within said cemetery, after a reasonable search for such remains, as in ORS 226.520 defined, has been conducted, are removed in a manner reasonably providing for respectful and careful treatment of such remains, and providing for reinterment and recommitment, in a respectful manner.

(b) If the identity of remains is preserved in so far as reasonably practicable, having due regard to the conditions of the cemetery, the condition and location, or dislocation of stones and monuments, and other factors related to the particular project, and, in so far as practicable, the identity shall be shown upon the relocation of said graves in a new location, by the erection of suitable markers at the location of such graves.

(c) In the event that there are remains in such cemetery which cannot be identified, all of such remains may be interred in a section of the new cemetery site, and the same may be marked by one suitable monument, which shall contain the names of persons, known to have been interred in said cemetery, but whose remains could not be identified.