Final Report on the Archaeological Intensive Survey for the Thompson Island Salt Marsh Restoration Project, Boston Harbor Islands, Massachusetts

Summary

A salt marsh restoration plan for Thompson Island in Boston Harbor calls for the removal

of a stone berm that prevents tidal flushing of an existing salt marsh/pond on the central

east side of the island. Lack of daily tidal exchange has resulted in a stagnant water body

with severe algae blooms and encroachment by the invasive plant species, common reed

(Phragmites australis). The restoration plan includes archaeological investigation of the

proposed construction/demolition area as well as the inter-tidal zone and marsh/pond

bottom that may be subject to erosion once the blocked outlet is reopened. The

construction area was tested with a series of ten, 10 m-interval shovel tests arranged in

four transects. Sand and gravel predominated with a low density of late nineteenth and

twentieth century waterworn ceramics, glass, brick and coal. The south and west marsh

perimter was previously tested with 20 m-interval shovel tests by Barbara Luedtke in

1993 with only late nineteenth and twentieth century artifacts found. The remaining east

and north tidal zone, therefore, was tested with nineteen, 20 m-interval shovel tests.

These revealed sandy clay loam soils and a low density scatter of mostly waterworn late

nineteenth and twentieth century artifacts. Two gray siltstone flakes and some shatter

were identified in one test in [REDACTED]. Array tests

revealed an additional gray-green chert flake. The marsh bottom was remotely imaged

using a StrataBox subbottom profiler to search for potential submerged anomalies.

Shallow conditions and gas-charged sediments obscurred some readings, but a paleo

drainage channel was identified approximately 2 m below the marsh bottom. Although

one small Native American activity locus was identified, it was

recommended that the project proceed as planned.

Keywords

Spatial Coverage

Notes

Redaction Note: Information relating to the location of prehistoric sites, features, and artifacts has been redacted from this document.

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