Perimeter Investigations of the Lamar Unit, Ocmulgee National Monument, Bibb County, Georgia

The Lamar Unit of Ocmulgee National Monument sits on the Ocmulgee River bottoms about two miles south of the main unit (Fig. 1). Work at the Lamar Unit boundary was begun in October, 1996, by Eagle Scout candidate John Humphery under the direction of National Park Service (NPS) Ranger Todd Nelson. The goal of the Eagle Scout project was to remove vegetation from the boundary and a belt external to the Lamar Unit for an ATV trail to be used by monument staff and local hunters while discouraging ATV trespassing on the Lamar Unit. Land surveyors volunteered time and equipment to relocate the original twelve concrete boundary monuments and property line as perimeter clearing progressed (Fig. 2). During the perimeter clearing, it was evident that several boundary signs required replacement, and others attached to trees needed to be moved nearer the relocated boundary. Further, the top of one boundary monument was found at ground level and a second boundary monument was entirely buried. Therefore, it was decided that new boundary signs mounted to new posts should be installed adjacent to each concrete boundary monument to aid their future relocation as well as to mark the boundary. The decision was made to erect additional boundary signs on newly installed posts approximately half way between the original boundary monuments and at other selected locations to further enhance boundary definition. In all, thirty-one posts with signs were installed along the Lamar Unit boundary (Fig 3). The posts installed near the twelve concrete monuments are two-inch diameter aluminum pipes cut to five-feet long. The aluminum posts have a metal plug at one end while the other end was cut with short parallel slits to form a one-inch flare for anchoring. New plastic boundary signs affixed to treated wood were bolted to the aluminum posts. The posts installed half way between the concrete monuments are two-inch diameter galvanized steel pipes cut to eight-feet long. The steel posts were anchored in the posthole with about one foot of concrete. Older but still usable large metal boundary signs were bolted to the steel posts. All of the posts were set in three-foot (90 cm) deep holes. In addition to the installation of the posts and boundary signs, incorrectly placed signs were removed and reattached to trees along the boundary, and the perimeter was policed of barbed wire that once marked portions of the Lamar Unit boundary. To meet the Section 106 objectives to protect the cultural resources at the Lamar Unit, the postholes for the posts were dug following the archeological methodology presented by Abbott and Neidig (1993). The soil was extracted in 10 cm increments with a 16 cm diameter scissors postholer. The extracted soil samples were inspected and briefly described (texture and Munsell® color) prior to screening through'/4 inch mesh hardware cloth; the fill materials of the levee were inspected and briefly described but were not screened. Any items left in the screen were collected and placed in an appropriately labeled level bag. All of the postholes were excavated to a depth of 90 cm (3 ft.).