The Posey site (18CH281) is located on Mattawoman Creek at the Indian Head Division of the Naval Surface Warfare Center in Charles County.  The site was occupied during the second half of the 17th century, probably by Native Americans, who manufactured and reprocessed trade goods.

Archaeological Investigations

The Posey site was initially tested by William Barse during a survey of limited portions of the Naval Surface Warfare facility in 1985.  Researchers from Jefferson Patterson Park and Museum returned to the site in 1996.  Fieldwork consisted of the excavation of 510 shovel test pits and 37 test units.  Cultural features (including postmolds, possible pit, and midden deposits) were uncovered or excavated.

Approximately 8,000 artifacts were recovered during the 1996 investigations, including large amounts of ceramic and lithic materials, hand wrought nails, brass fragments, bottle glass, and glass and shell beads.  The ceramic assemblage was predominantly composed of Potomac Creek Plain, with lesser quantities of Camden, Yeocomico, and various European  types.  The lithic inventory included European flint as well as local quartz, quartzite, and chert.  Additionally, 4,000 faunal elements were recovered, consisting primarily of bone fragments from taxa indicative of woodland and riverine environments. 

Archeobotanical Studies

Plant studies associated with archaeological investigations at the Posey site included the collection of flotation samples for the recovery of plant macro-remains, waterscreen recovered macro-botanicals, and the analysis of two pollen cores from Mattawoman Creek.  A possible maize fragment and nutshell fragment were noted during Barse’s 1985 excavation of Feature 1, and are associated with an uncalibrated radiocarbon date on wood charcoal of 375 +/- 90 BP (Barse 1985:158; Potter 1993:144). 

Grace Brush analyzed two pollen cores taken from Mattawoman Creek adjacent to the Posey site in order to reconstruct a history of wetland vegetation.  Core 1 measured 123 cm in length, Core 2 was 93 cm long.  Radiocarbon dates were obtained from the basal sediment of each core, with each core spanning approximately 600 years of history.  Pollen profiles from the two cores yielded similar results.  Variation between the cores is attributed to differences in sedimentation rates as well as to differences in local distribution of plants.  Pine was the dominant taxa.  The two cores show a pine-dominated wetland vegetation that varies in degree of wetness over time, with some spatial variation.  Other trees represented include walnut, oak, sweetgum, and hickory, which are characteristic of more mesic vegetation.  Herbaceous vegetation includes a number of wetland species.  The pollen core results are remarkable in that there is no indication of the effects of deforestation or agriculture on the wetland landscape. 

A full, quantitative analysis of the waterscreen and flotation – recovered macro-botanical remains was accomplished in November, 2011.  Seven flotation samples and five water-screen recovered floral samples were studied.  All of these sampled hailed from a large midden excavated in 1996 at the western edge of the core area of the Posey Site.  This rich midden contained a high content of cultural material, and eight sections were excavated, revealing a shallow trough with curving base.  There were no structural remains associated with the midden feature. 

A total of 11.175 grams of carbonized plant macro-remains were recovered.  Wood charcoal (1,402 fragments weighing 8.66 grams) was dominated by oaks, with pine and hickory.  Nutshells were scant, with only 16 fragments (0.18 grams).  Carbonized seeds (six) were predominantly grape.  The samples were extremely maize-rich, with 524 fragment weighing 2.295 grams recovered.  A variety of morphological elements were identified, including cupules, cupule fragments, and kernel fragments.  Two pieces of unidentifiable amorphous carbon were also recovered.  Uncarbonized seeds were abundant and ubiquitous within the Posey Site floral samples. 


Beta Lab No

Age BP

Cal 2 sigma low

Cal Median Probability

Cal 2 sigma high

Feature 1


375 +/- 90 BP*

AD 1330

AD 1542

AD 1951

Base of Pollen Core 1


640 +/- 60 BP**

AD 1272

AD 1344

AD 1413

Base of Pollen Core 2


630 +/- 70 BP**

AD 1268

AD 1346


* Measured Age
** C-13 Adjusted Age


Barse, William
1985 A Preliminary Archeological Reconnaissance Survey of the Naval Ordnance Station, Indian Head,
  Maryland Historical Trust Manuscript Series, No. 40.
Brush, Grace
1999 Pollen Study of Two Sediment Cores from Mattawoman Creek, Maryland.  Appendix D to
Archaeological Investigations at the Posey Site (18CH281) and 18CH282, Indian Head Division,
Naval Surface Warfare Center, Charles County, Maryland. 
Jefferson Patterson Park and Museum
Occasional Papers Number 7
Harmon, James M.
1999 Archaeological Investigations at the Posey Site (18CH281) and 18CH282, Indian Head Division,
Naval Surface Warfare Center, Charles County, Maryland.
  Jefferson Patterson Park and Museum
Occasional Papers Number 7.
McKnight, Justine W.
2011 Archeobotanical Remains Recovered from a Middle to Late Seventeenth Century Midden at the Posey Site (18CH281).  Report submitted to the Maryland Archaeological Conservation Laboratory, Jefferson Patterson Park and Museum, St. Leonard, Maryland.
Potter, Stephen R.
1993 Commoners, Tribute, and Chiefs: The Development of Algonquian Culture in the Potomac Valley.
Charlottesville: University Press of Virginia.

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