Summer 2006 Fieldwork Update: Diagnostic Lithics and Radiocarbon Dates begin to shed light on the Chronology at the Blueberry Site (8HG678)

By: David Butler MA, RPA

 

This summer Professor Butler and his students from UCF and Valencia Community College continued working to complete the assessment of the parcel containing the Blueberry site.  This summer’s work has been highly productive and we are beginning to gain insight into at least one component of the spatial and temporal dimensions of the site. 

The test pit grid (high probability grid = 25 meter interval between test pits) is virtually complete.  There are still a few judgmental bounding test pits (less than 25) and a very small area (less than one acre) in the southeast corner of the property has yet to be assessed.  In addition to identifying the extent of the site along the ridge south and west of last year’s grid work, the work done on the test pit grid over the summer produced several diagnostic projectile points.  For example, one late archaic/early woodland Culbreath point (in the center of a midden context containing sand tempered plain and Belle Glade plain pottery) was found.  Also, four Pinellas points (Mississippian points from the same midden context as the Culbreath; found closer to the surface than the Culbreath) and three Hernando points (Woodland points; found in the same stratigraphic context as the Pinellas) were discovered.  These are highly significant artifacts for this site because they add to the relatively sparse lithic assemblage of Highlands County and because they provide a basis of comparison with other sites around the state where their temporal context has been established.    

One significant step taken to maintain spatial control of the test pit grid was taken over the summer.  Each positive test pit location was recorded with a highly accurate hand held GPS device (Garmin GPSmap76CX).  This spatial data provides detailed longitude latitude coordinates for each of the positive test pit location.  These grid points were then downloaded from the GPS onto a computer, integrated into GIS software, and used to produce aerial and topographic maps illustrating the extent of the site.  These maps and the coordinates of each positive test pit will be included in the Blueberry site report along with the results of detailed lab analysis investigating individual test pits and an overall assessment of all test pits. 

The data recovered from test pits will complement data recovered from a series of Test Units designed to concentrate on the most significant areas of the site and provide the opportunity for identifying intact features.  The Test Unit (2X2 meter block unit) that was open last year (previously known as XEA4; now known as Test Unit 1) was completed over the summer (the field crew is forever grateful for Charles Reynolds taking the time out of his busy schedule to backfill the unit).  This unit was excavated to a depth of 260 cmbd (250cmbs).  An archaic layer comprised mostly of finish flakes/pressure flakes persisted until 240 cmbd.  The final 20 centemeters (240-260 cmbd) of the unit was sterile (contained no artifacts).  This is good because otherwise Professor Butler would not be able to sleep at night wondering what might have happened if we had dug a little deeper… 

Two distinct middens were present in the stratigraphic profile atop the archaic occupation.  They were separated from the archaic layer by 50 centimeters of white sand with a very low density of artifacts.  They were separated from each other by 30 centimeters of white sand with a relatively low density of artifacts.  These anthrosols (soil horizons/stratigraphic layers created as a byproduct of human activity) were much darker than the surrounding strata (10YR 4/1 brown –vs- 10 YR 7/1 light grey) and contained multiple features including over 20 post molds and three hearths.  Additionally, these midden strata contained a very dense artifact assemblage dominated by sand tempered plain and Belle Glade plain pottery. 

One charcoal radiocarbon sample was processed from each of these midden contexts.  Additionally, the carbon residue (residual protein from what was previously cooked in the pot) from the inside of a pottery sherd was assessed from the upper midden context (the midden closest to the surface).  The organic residue from this Belle Glade flat rim sherd produced a calibrated radiocarbon date (2 sigma) of AD 1400 – 1460.  The calibrated radiocarbon date (2 sigma) of the charcoal from this midden context is AD 1230 – 1300 (the sherd came from 12 cm above the charcoal).   The lower midden returned a calibrated radiocarbon date (2 sigma) of  AD 1160 – 1280.  These distinct stratigraphic layers and their associated radiocarbon dates correlate nicely with the diagnostic projectile points discovered in the same strata along the same landform from test pit contexts. 

We are currently excavating the second 2X2 meter block Test Unit.  This unit will provide our first opportunity to compare radiocarbon samples from the same stratigraphic layers from separate areas of the site.  This step will begin to generate a comprehensive understanding of variation in the landscape (such as differential erosion, sediment accumulation, or disturbance) that may affect the stratigraphic and temporal association of artifacts and features across space and through time at this highly significant landscape.