Take photos from different angles. Mark relevant evidence with flags or other visible markers beforehand. The goal is to document the scene as it existed before the anthropologists alter it in any way. A datum positioned 2 to 3m SW of the remains works best. Alternatively, bury a large scrap of metal that can be located later with a metal detector.
Telephone poles are excellent reference points, as they usually have a unique utility number.
The top of the datum stake should be higher than highest point of burial mound. Make sure to record the BD value on on field data form. Lay out a baseline Use the datum stake as one end of the baseline. Hook the metal loop of a 30 or 50m tape on the datum nail and lead out the tape. Alternatively, lay out the baseline for convenience and plot its compass bearing afterwards.