encloses. Layers of earth -- their texture, color, other substances inter-mixed, chemical composition and microscopic particles -- may tell a trained observer the exact circumstances prevailing at the time of burial. Sometimes the layering of earth provides the only clue to the age of objects.

Should possible evidence be uncovered, excavation should cease until the nearest university or historical society has been asked for further instructions. Sites of likely importance should be guarded until professional help arrives. If this is not practicable, the excavation should be refilled with the original dirt and carefully marked to await expert examination.

If, despite this urgent recommendation, it is felt the objects must be removed, the finder should at least make close-up color photos. Also a sketch should be prepared of the site and the artifacts in

place relative to some permanent landmark. The depth and any noticeable layering of earth should be recorded.

A sample of earth adjacent to artifacts, and a control sample from a clear site nearby, should be kept in clean jars or plastic food bags for phosphate analysis.

Wood, charcoal or bone found in association with the find should be handled with a tool. Organic material should NEVER be picked up with the hand. Uncontaminated organic material often can be dated by delicate atomic chemistry. However, the process is rendered inaccurate by the faintest trace of sweat or body oil.

Organic material removed from mud or water should be kept immersed until it can be properly preserved. If allowed to dry out, perishable objects will disintegrate irrevocably.