Cobb

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Cobbs Point-Culpeper RebellionArchaeology Team

• Member Donquel Davis
• Member Kevin Brodie II
• Mentor Dr. Malcolm LeCompte

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Members
Donquel Davis
Kevin Brodie II
Dr. Malcolm LeCompte
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Abstract

• During the decade of 1670 to 1680, political
  maneuverings were initiated by prominent property
  owners north of Albemarle Sound with the ultimate
  intent of obtaining control of the lucrative
  tobacco trade developing between New England and
  the mother country. These activities, aggravated
  by severe weather and low crop yields, and a
  perception of excessive crown taxation erupted in
  a bloodless rebellion against the laws and
  governance of the crown. The rebellion was
  ultimately resolved peacefully and without
  significant bloodshed. The center of activities
  during these events was the courthouse and
  customs house reported to be located on the
  Pasquotank River at Cobbs Point, South of the
  current center of Elizabeth City. Early maps
  show a building near the shore with another
  rumored to be nearby, not far from the foot of a
  dock at which shipments of tobacco were sent to
  customers. Anecdotal evidence and local
  tradition hold the two buildings to be located
  near or incorporated into structures located on
  the Winslow Farm which was developed into a
  subdivision around 1960. This land has recently
  become available and accessible for an
  exploratory survey to ascertain the location of
  any historically significant structures and to
  determine the extent of any remains that may yet
  exist.

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Abstract continued

• Aerial photos of the Elizabeth City area, made
  prior to and just after World War 2, were
  examined to determine the location of the
  original shoreline and any structures that may
  have contained elements of the original colonial
  era buildings. Modern Digital Orthographic
  Quarter Quad (DOQQ) aerial photographs were used
  to provide geo-referencing of the early aerial
  photographs. The geographic coordinates of
  structures formerly occupying the Cobbs Point
  site defined an area that allowed a Ground
  Penetrating Radar (GPR) survey to be made. The
  purpose of the survey was to reveal whether any
  remains of earlier structures are present. The
  area was covered in transects enabling linear
  data to be collected. Transects were made at
  sufficiently small separation to allow computer
  processing aided re-construction of a
  three-dimensional visualization of what lies
  beneath the surface to a depth of about 3 meters.
  The features appear to be present within the
  soil depth probed by GPR, their nature and exact
  location may be determined by a trained
  archaeologist using a probing device to
  physically penetrate the soil at locations
  revealed by the GPR survey. Sufficiently
  interesting results prompted a request to the
  property owners to allow excavation of any
  structural remains that have been discovered.

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Map of Cobbs Point 1775
Courthouse was the center of the Culpeper
Rebellion
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Objective

• Use modern technology to discover remnants of the
  buildings/structures that were critical to these
  historic events.

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Methodology to the Historical Site Survey

1. Old maps from 1775, 1850 (UNC Archive)
2. Aerial photos from 1938 (provided by R.B. Long)
   and 1993 DOQQ (USGS)
3. Anecdotal Stories confirm and connect the
   structures
4. 1938 photo and geo-rectified it to 1993 DOQQ
5. Relayed info back to lead Archaeologist Edward
   Clay Swindell
6. GPR survey on the site slightly adjacent to our
   original findings led by the lead Archaeologist
7. Processed data readings from GPR survey
8. Created a 3D image and analyzed data using RADAN
   6.6 software
9. Reported results to Edward Clay Swindell for
   further GPR surveys of the surrounding areas and
   future excavation on the site

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Map of Cobbs Point 1850
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Actual Aerial images

• 1938

• 1993 DOQQ

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Exelis ENVI 4.7

• The team then used Exelis ENVI software to find
  common geographic points so they would be
  co-registered and we could begin warping the
  photos.
• ENVI is the premier commercial software
  solution for processing and analyzing geospatial
  imagery.

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Geo-Referencing and Warping

• With the aerial photos now warped and
  co-registered they share geographic coordinates.
• The team then enhanced the images to increase the
  contrast lighting.

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Shore line and Structure Overlay
1938
1993 image with 1938 features
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Field Work

• After all our images were processed the team then
  visited the site to begin marking with flags
  where the two barns were using the
  geo-coordinates given by ENVI.

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Change of Plans

• The team then relayed this information to Edward
  Clay Swindell the Archaeologist that directed
  our data collection.
• Edward Swindell pointed out a change in surface
  appearance on land adjacent to the location our
  analysis had indicated for the barn-like
  structures.
• The team followed the archaeologists lead and
  set up a 25x25 m grid. In this area the team
  commenced the GPR survey.

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New Area of Interest
New area for GPR Survey
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Ground Penetrating Radar?
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Set Up for GPR survey
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GRID


NW
SW
1 meter apart
SE
NE
Tree
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Actual Shot of the Grid
Infamous bush that gave the team issues
Stopping line
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Surveying with GPR
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RADAN 6.6
Monitor
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GPR Readings
16 meters between subsurface features
16 meters between subsurface features
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3D Figures
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Data Readings and Results
chimneys
Possible foundation for chimneys (16 meters
apart)
A typical early colonial home, roughly
contemporary to the courthouse and customs
building at Cobbs Point.
After maximizing the quality of the files, the
team then created a 3D image.
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Slices
.68 m depth
Shows the chimney foundation persisting almost 2
feet into the ground
1 m depth
1.34 m depth
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Conclusion

• All in all, the GPR survey gave the team
  promising results that there were subsurface
  features. It revealed the presence of a structure
  whose identity remains unknown until future work.
  

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Future Work

• Led by Edward Clay Swindell (Archaeologist)
  additional GPR surveys may be taken in areas
  surrounding the original GPR survey grid.
• Also sonar may be done in the surrounding water
  areas to reveal relics of the dock. (e.g. dock
  pilings or piling holes)
• Physical probing or excavation may be done of the
  subsurface features revealed by the teams work.

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Problems Encountered

• ENVI 4.7 angle of observation, sunlight, and
  shadows caused ground control points uncertainty
• Field Work with GPR inconsistent lengths of the
  transects, GPS coordinate uncertainty, battery
  failure and rebooting issues
• RADAN 6.6 graphics card wouldnt allow RADAN to
  be accessed on Mac, incorrect approaches to
  rendering a 3D Display

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Questions?