Thornhill Archaeological and Historical Site (23SL220)

Excavating the mass of corn kernals found on the floor of the prehistoric house at Thornhill

Neathery Batsell Fuller holding a stadia rod during the mapping of the postmolds (marked by yellow stakes) and the floor of the prehistoric house at Thornhill during summer of 1981.

Artifacts, ecofacts, and features found on the bluffs behind the Thornhill plantation house indicate that the Native American occupation of the site began around 8,000 BC and ended in approximately AD 1100.

Thornhill is situated on a bluff line of the Missouri River Valley. Dozens of archaeological sites are scattered along the bluff. Nearby is the highly significant Paleo-Indian site discovered by Dick Martin and partially excavated by Julie and Toby Morrow (from Washington University).

The singlemost significant discovery at 23SL220 was a Mississippian Period house that burnt shortly after being filled with an abundant harvest of 10 and 12 row corn. The wall trench house measured 6.75 by 4.85 meters and was set in a shallow basin about 30 centimeters deep. A carefully prepared firepit was situated near the center of the house and most of the floor surface had been covered with a woven mat of cattails or similar reeds. The west portion of the floor was not covered with the mat and probably served as a raised sleeping bench.

A radiocarbon date of AD 1100 +/- 70 corrects to AD 855 for the mass of carbonized corn kernals and cobs found in the interior of the house. The pottery sherds from the interior of the house reflect both shell tempered and limestone tempered wares. Most sherds are plain surface, but a few were either red slipped or cordmarked. The conclusion of the excavator (Neathery Batsell Fuller) is that the house is Emergent Mississippian in age (ca. AD 855) but other archaeologists have treated it as a Stirling or Moorehead Phase structure based upon the uncorrected radiocarbon date. They dismiss the limestone tempered sherds as natural components of the soil fill or the continuity of "Late Woodland" pottery traditions well into the mature phases of the Mississippian Period.

Contour map of Thornhill showing the Bates Plantation home (lower edge) and distribution of 2 x 2 meter test pits excavated by Washington University archaeologists in 1981. The Mississippian House feature was discovered in excavation unit N108 E90.

Mississippian house showing post mold patterns interpreted as a fire screen and raised sleeping platform.

Mississippian house showing the concentration of carbonized corner in the southeast corner of the room.

Mississippian house showing the distribution pattern of mat impressions on the packed clay floor of the house.

Profile plans for all four wall trenches of the Mississippian house at Thornhill

Aerial Photograph of the Mississippian Period house during excavation, summer 1981.

Closeup of the aerial photograph of the Mississippian Period house during excavation, summer 1981.

Wall trench on north side of the burnt Mississippian Period house. Yellow tent stakes have been placed where an upright post could be identified in the trench.

Wall trench on south side of the burnt Mississippian Period house. Yellow tent stakes have been placed where an upright post could be identified in the trench.

Remains of a carbonized basket found next to the hearth in the center of the house.

Neathery Batsell (left) supervising two students excavating in unit N0 E74 at 23SL220.

Two evening college student shovel skimming the test unit in N0 E74 at 23SL220.

Carbonized corn discovered during test excavation of unit N100 E90 at 23SL220.

Undergraduate students carefully shovel skimming the soil in excavation unit N100 E90.

3 side-by-side excavation units that exposed the south margin of a mass of carbonized corn inside the interior of a Mississippian Period house.

Carbonized corn encountered during the spring of 1981 testing at 23SL220.

Contact between the plowzone (top 20 cm.) and undisturbed deposits in excavation unit N112 E90 at 23SL220.

Neathery Batsell and three undergraduate students working in excavation unit N116 E68 during the spring of 1981.

WU student archaeologists using shovels to skim remove the plowzone in excavation unit N6 E98 during spring of 1981.

Test pit N6 E98 with the first 10 cm. of plowzone removed during spring of 1981.
Contact between plowzone and undisturbed soil in excavation unit N6 E98 during spring of 1981.

Tripod and screen used to sift 100% of the fill from excavation unit N6 E98. All soil fill excavated from 23SL220 was sifted during the 1981 field season.

Excavaton unit N90 E100 at the edge of the blufftop.

Excavations units at the south end of 23SL220 near the Bates Cemetery.

Tammy Bennington (left) and another WU undergraduate student running elevation measurements with a transit at 23SL220.

Profile drawing by Neathery Batsell of a Late Woodland Period trashpit in excavation unit N6 E98 situated in the southern portion of 23SL220.

Bob and Evan using the flotation machine to recover carbonized plant remains from the soil of 23SL220.

High school students pouring soil into the flotation machine used by Washington University archaeologists on several projects.

Light fraction composed of wood charcoal and carbonized seeds being skimmed from the surface of the water in the flotation machine.

Overflow water being collected and sieved to recover very fine pieces of charcoal.

Mat impression on the floor of the prehistoric house.

Small, complex feature in the interior of the Mississippian house.

Bell shaped pit pierced by a later cylindrical pit inside the Mississippian house.

High school student volunteer uncoverering the wall trench of the prehistoric house.

High school student volunteer measuring a mass of soil and daub interpreted as clay bench.

Corn mass as uncovered during Spring 1981.

Site Constructed 19 October, 2001
Revised on 22 February 2012