Tuesday, October 16, 2012

2012 field school at French’s Tavern

Site A overall with Crystal facing west

We just finished up the 2012 field school at French’s Tavern at the larger Indian Camp site. The purpose of the field work was to locate a quartering site dating from 1730-1777, the period of ownership of Francis Eppes, then John Wayles, and then Thomas Jefferson.

44PO158 covers an area of about 85 ft. x 125 ft. that is located at a field edge and extends into the adjacent forest. This field season, we laid out 10 5 ft. x 5 ft. units along the field edge in two rows in a checkerboard pattern in hopes of locating features associated with a possible slave quarter.

In the far southwest unit we found a large feature extending out of the northwest corner of the unit. We opened up another unit along the northern wall and the feature continued into that unit. It appeared to form to corner of a larger square or rectangle. We mapped the portion of the feature that was exposed and cored it with a small diameter coring tool. The soil contained within the core was uniformly silty from top to bottom, indicating that the feature contains a single layer of fill that probably represents sediment deposited from heavy rain. The core results suggest that the feature may be a tree-fall or other natural depression.

Katherine and Lauren mapping at Site A
In the other excavation units, we have found many artifacts that could relate to the target time period, but are not precisely dateable. For example, we’ve found many brick fragments, pieces of charcoal, fragments of dark green wine bottle glass, and hand wrought nails or fragments. We have also found sizeable pieces of iron that we have not yet identified.

The ceramics from the site are more dateable. Two types were made and used within our period of interest: English brown stoneware and creamware. The greatest concentration of these ceramics is on the eastern side of the northern line of units, closest to the forest edge. Fragments of Chinese porcelain may also date to this period, or may be later. Pearlware sherds, which date after 1780, have also been found at the site.

Large feature at 44PO158
A quick look at the spatial distribution of these artifacts may indicate that we are excavating at the edge of a site located slightly farther to the north, in the woods. Due to plowing, drainage and erosion, some of the artifacts may have moved down slope from the east, west, or south due to the sloping landscape of the site.
 Further work relating to the site will include analyzing artifacts and samples in the lab. 

Written by: Kathryn Gard 

Wednesday, October 3, 2012

Geophysics at Indian Camp

Gradiometry: Stephen and Crystal with gradiometer
In early June, Dr. Gerald Schroedl and Stephen Yerka came to explore the French’s Tavern subsite of Indian Camp with noninvasive surveying equipment.  Once the 20 meter grids had been shot in with the total station, I was able to assist during the process of surveying Site B with a gradiometer. Because the gradiometer functions by measuring changes in the earth’s magnetic field, Stephencould not wear any metal while operating it. We also had to remove the nails from the corners of the excavation units or the instrument would have registered them and the readings would have been essentially useless.

In order to take systematic readings across the grid, ropes were laid out and one had to be moved at intervals as a guideline for each transect—meaning that Dr. Schroedl moved one end of the rope and staked it into the ground, and I moved the other end the same distance. Then Stephen walked along the line (rope) at a pace of one meter per beep of the metronome on the gradiometer, and took a reading at each beep.

gradiometry: Stephen and Aaron with gradiometer
The readings taken by the gradiometer were then entered into a computer program by Stephen, where he could map the data. The magnetic anomalies were displayed on the map and could be clarified by “despiking,” which edits out high magnetic readings that would otherwise obscure the less obvious, but potentially meaningful, magnetic disturbances within the grid.

Rachel pulling ropes
Once the data are properly processed, gradiometry can provide useful information about a site and help direct decisions about where next to excavate.

Blog written by:

Rachel Guy