Introduction – Field Methods & Findings – Forensics

Archaeology

BEACON ISLAND GRAVE SITE Remains of 6 people in mass grave

Beacon Island Burial Sites
Human skull fragments were discovered in the 1980s on Beacon Island by fisherman digging a leach drain from their privy behind two of the shacks. These finds remained unreported until the Commonwealth Historic Shipwrecks Amnesty in 1993–1994 from prosecution under the Historic Shipwrecks Act 1976. A team from the Western Australian Maritime Museum partially excavated the grave site in 1994 finding skeletal material from two adults and a child.

In 1999 the excavation area was enlarged to 5 square metres and the remains of five individuals (SK7, SK8, SK9, SK10 and SK11) were removed from a mass grave.

The bodies were found to lie over, under, or in, a large deposit of black, dense soil penetrated by numerous fines roots… Embedded in these black deposits were metal buttons, some fibrous material and impressions of woven, fibrous material, which may indicate the presence of fabric. Since this black deposit obviously needs special care and investigation it was left in situ for future investigation.

In 2001 the excavation of the mass grave resumed.

Excavation Methods and Analysis
Field methods
The excavation of the grave opened up the 6 squares from 1999 and removed backfill to the level of the upper part of the solid mass. The aim was to remove intact the dense soil feature at the centre of the grave: accordingly the areas around the mass were excavated in 5 cm spits. Eventually the mass sat on a pedestal of crushed coral and sand.

The removed soil was sieved in 5mm and 3mm sieves and residues searched both on site and - due to the slow detailed sorting required - later in the Maritime Museum. This was how the teeth of the infant (SK12) were located, as the deciduous teeth are almost indistinguishable within the crushed coral and shell matrix that constitutes Beacon Island.

The dense matter required careful treatment during excavation and removal. During excavation the mass was constantly kept damp to avoid the black matrix and the protruding human bones from drying out. Photographic techniques followed those developed earlier to create a 3D photo model of the mass. A wooden box was built around the mass and then packed with sandbags and hardened foam for transport to the Maritime Museum in Fremantle.

Analysis of dense soil feature
The analysis of the grave contents at the Maritime Museum involved several techniques:
(1) the grave mass was x-rayed revealing the location of artefacts and bones;
(2) the matrix was then excavated in thin layers of one centimetre.
The time afforded by excavation at the Museum allowed the bone fragments to be carefully removed and their position carefully plotted with photogrammetry. The matrix was a thick vegetable material combined with soil and intrusions of white material. Samples were taken for AMS dating from the organic material that had formed inside the long bones; this meant that if the dark matrix had formed in 1629 or shortly afterwards it could be dated.

Discussions with archaeologists who work with mass burials indicated that the solid mass was a rare formation that had not been seen in other contexts. Consequently, a sample of the mass was retained whole in the museum collection.

Findings
Individual human remains
The removal of human skeletal material allowed more complete assemblies of the skeletons. As a result it is possible to state that there were six individuals in the grave: three adults, a teenager, a child, and an infant (Table 1). The infant SK12 was represented only by 19 teeth. Only one skeleton showed visible trauma (SK6+SK10), however this does not rule out a violent death for the remainder as murder by drowning or a cut throat (two common methods on the islands) would not leave evidence of trauma on the bones.