Ground Penetrating Radar (GPR) Investigations at the Jesup

Railroad Depot, Wayne County, Georgia

GDOT Project CSMSL-0008-00(691)

PI# 0008691

Prepared for:

Cypress Cultural Consultants, LLC

41 Sherman Drive

Beaufort, South Carolina 29907

And:

Bron Cleveland Associates, Inc.

16-B Lenox Pointe, N.E.

Atlanta, Georgia 30324

By:

Sara H. Gale

____________________________

Principal Investigator

Georgia Department of Transportation

Office of Environment/Location

3993 Aviation Circle

Atlanta, Georgia 30336

October 27, 2008

ii

ABSTRACT

On July 30, 2008, staff archaeologists from the Georgia Department of Transportation

(GDOT) conducted a series of ground penetrating radar (GPR) assessments of selected

areas surrounding the Jesup Railroad Depot, in Wayne County, Georgia. This work was

completed as part of the assessment of Site 9WY93 for Cypress Cultural Consultants,

LLC, the Consultant, and Bron Cleveland Associates, Inc (BCA).

The City of Jesup, working with BCA and GDOT, is planning to rehabilitate the railroad

depot in Jesup. The rehabilitation will include repaving the parking lot, providing

landscaping, restoring the exterior of the depot, repairing and restoring the interior, and

re-roofing the existing roof. This geophysical survey is part of the environmental impact

analysis being completed prior to the start of the rehabilitation project.

The primary focus of this work was to identify the horizontal and vertical extent of site

9WY93 and any associated features. Approximate depths of these features were

determined to aid in the evaluation of impacts from the portion of the proposed project

that will repave the parking lot. Repaving will involve removing the existing asphalt,

regrading as necessary, and repaving the lot. The regrading process has the potential to

impact approximately 30 cm below the ground surface.

Results from this survey were utilized to verify the location of several buried utilities and

identify an old entrance or pull-through for the depot, possible former tree locations, and

several other anomalies. None of these features will be adversely impacted by the

rehabilitation project, including the repaving or regrading of the parking lot.

iii

TABLE OF CONTENTS

Page

Abstract ............................................................................................................................... ii

List of Figures .................................................................................................................... iv

List of Tables .......................................................................................................................v

Introduction ..........................................................................................................................1

Methods................................................................................................................................3

Results and Interpretations ...................................................................................................7

Conclusions and Recommendations ..................................................................................17

References Cited ................................................................................................................19

iv

LIST OF FIGURES

Figure Page

Figure 1. Location of GPR survey grids adjacent to the Jesup Railroad Depot. ................ 2

Figure 2: GSSI SIR-3000 GPR unit with attached 400 MHz antennae. ............................. 5

Figure 3. Sketch map of grid layout around the Jesup Railroad Depot. ............................. 6

Figure 4: Amplitude Slice-Maps for Grids 1, 2, & 3. ......................................................... 8

Figure 5: GPR profile 2 from Grid 1. ................................................................................. 9

Figure 6: Feature 1, railroad tracks visible on the ground surface. ..................................... 9

Figure 7: Railroad track spur visible on the ground surface and located within Grid 1. .. 10

Figure 8: Linear utility features. ....................................................................................... 10

Figure 9: Photograph of Grid 2 facing northwest. ............................................................ 11

Figure 10: Parking lot where Grids 4 & 5 were located. .................................................. 11

Figure 11: Amplitude Slice-Maps for Grids 4 & 5. .......................................................... 12

Figure 12: Feature 2, former depot entrance. .................................................................... 13

Figure 13: Aerial Photograph of a portion of downtown Jesup taken in 1959. ................ 14

Figure 14: GPR profile 48 from Grid 4. ........................................................................... 15

Figure 15: Feature 3, possible historic tree location. ........................................................ 15

Figure 16: GPR profile 50 from Grid 4 ............................................................................ 16

Figure 17: Water line ........................................................................................................ 16

Figure 18: Location of features visible in the GPR data. .................................................. 17

v

LIST OF TABLES

Table Page

1. Summary Information for GPR Grids..............................................................................5

1

INTRODUCTION

On July 30, 2008, staff archaeologists from the Georgia Department of Transportation (GDOT)

conducted a series of ground penetrating radar (GPR) assessments of selected areas surrounding

the Jesup Railroad Depot, in Wayne County, Georgia (Figure 1). This work was completed as

part of the assessment of site 9WY93 for Cypress Cultural Consultants, LLC., the Consultant,

and Bron Cleveland Associates, Inc (BCA).

The City of Jesup, working with BCA and GDOT, is planning to rehabilitate the railroad depot in

Jesup. This geophysical survey is part of the environmental impact analysis being completed

prior to the start of the rehabilitation project. GDOT personnel who helped with the geophysical

survey on this project included Sara Gale and Heather Mustonen. Two other GDOT employees

from the Testing Management District 5 Laboratory, David Graham and Kevin Leonard, also

helped with the July revisit to site 9WY93.

A Phase I archaeological survey was conducted by Cypress Cultural Consultants, LLC. on

March 14, 2008. This survey identified the entire APE of the rehabilitation project as site

9WY93, which is associated with the historic train depot and contains a mid-nineteenth century

residential component (Owens 2008:29). During this initial survey shovel test pits could only be

dug in areas that were not paved or covered with compact gravel. In order to identify features

beneath the paved area a geophysical survey and additional shovel test pits was determined

necessary to complete the assessment of site 9WY93. The geophysical survey was conducted by

GDOT archaeologists and the shovel test pits were completed by the Consultant with the help of

the GDOT Testing Management District 5 Laboratory.

Interpretations in this report were guided by previously identified features associated with the

depot in both a historic and modern context. Vertical locations of features identified from the

geophysical data are of great importance for the purposes of this work. Features located at least

30 cm below the ground surface (cmbs) do not have the potential to be impacted by the Jesup

Railroad Depot rehabilitation project since they are not within the vertical area of potential effect

of the project. Ground disturbing activities are supposed to be minimal and only extend to

approximately 30 cmbs. Therefore any features located within the first 30 cmbs have the

potential to be impacted by the project and features located deeper than 30 cmbs do not have the

potential to be impacted by the project.

2

Figure 1. Location of GPR survey grids adjacent to the Jesup Railroad Depot.

3

METHODS

Ground penetrating radar data are acquired by transmitting pulses of electromagnetic energy

waves into the ground from a surface antenna, reflecting the energy off buried objects, features,

or bedding contacts and then detecting the reflected waves back at the ground surface with a

receiving antenna. When collecting radar data, surface antennae are moved along the ground in

transects, typically within a surveyed grid. A large number of subsurface reflections are collected

along each line. As energy waves move through various subsurface materials, the velocity of the

waves will change depending on the physical and chemical properties of the material through

which they are traveling (Conyers 2004). The greater the contrast in the physical and chemical

properties between two materials at an interface, the stronger the reflected signal, also called

amplitude, will appear (Conyers 2004). When travel times of energy pulses are measured, and

their velocity through the ground is known, distance (or depth in the ground) can be accurately

measured (Conyers 2006). Each time a radar wave passes through a material with a different

physical or chemical property, the velocity will change and a portion of the energy wave will

reflect back to the surface and be recorded. The remaining energy will continue to pass into the

ground to be further reflected, until it finally dissipates with depth.

Depths to which radar energy can penetrate, and the amount of resolution that can be expected in

the subsurface, are partially controlled by the frequency (and therefore the wavelength) of the

radar energy transmitted (Conyers 2004). Standard GPR antennae propagate radar energy that

varies in frequency from about 10 megahertz (MHz) to 1000 MHz. Low frequency antennae

(10-120 MHz) generate long wavelength radar energy that can penetrate up to 50m in certain

conditions, but are capable of resolving only very large buried features. In contrast, the

maximum depth of penetration of a 900 MHz antenna is about one meter or less in typical

materials, but its generated reflections can resolve features with a maximum dimension of a few

centimeters. A trade off therefore exists between depth of penetration and subsurface resolution.

In this survey a 400 MHz antenna was used, which produced data of good resolution up to

approximately 2.75-3 meters below the ground surface. Below this depth, extraneous

background noise affected the signal, making resolution of any features difficult.

Success of GPR surveys in archaeology is largely dependent on soil and sediment mineralogy,

clay content, ground moisture, depth of burial, and surface topography and vegetation.

Electrically conductive or highly magnetic materials will quickly attenuate radar energy and

prevent its transmission to depth. The best conditions for energy propagation are therefore dry

sediments and soil, especially those without an abundance of clay. The soils at 9WY93 consist

of approximately Ona and Blandon sands, which are poorly to moderately well drained sands

underlain by sand subsoil (USDA soils series descriptions 2008). An abundance of sand should

therefore allow for good energy propagation.

The “time window” within which data were gathered was 50 nanoseconds (ns). This is the time

during which the system is “listening” for returning reflections from within the ground. The

greater the time window, the deeper the system can potentially record reflections. In this survey,

50 ns is equivalent to about 2.75 m in real depth. To convert time in nanoseconds to depth, it

was necessary to determine the elapsed time it took the radar energy to be transmitted, reflected,

4

and recorded back at the surface. This amount of time is estimated by the post-processing

software RADAN. All profiles and processed maps were then converted from time in ns to

depth in meters using this average velocity.

How well the antenna stays in contact with the ground surface will also affect the quality of data

collected. A good antenna coupling means that there is a consistent distance between the bottom

of the antennae and the ground surface. Since an antenna can never be completely flush with the

ground surface, a consistent distance may be removed from the reflection profiles during data

processing to improve depth interpretations. A smooth paved parking lot is one of the best

scenarios for obtaining good antenna coupling. The paved areas surrounding the Jesup Railroad

Depot are not entirely smooth, but still allowed for an overall good antenna coupling during data

collection. During data processing a total of 3.71 ns were removed from all reflection profiles as

the distance from the antenna to the ground surface.

The initial data processing involved the generation of amplitude slice-maps (Conyers 2004).

Amplitude slice-maps are a three-dimensional tool for viewing differences in reflected

amplitudes across a given surface at various depths. Reflected radar amplitudes are of interest

because they measure the degree of physical and chemical differences in the buried materials.

Strong, or high, amplitude reflections often indicate denser buried materials, such as cultural

features. Amplitude slice-maps are generated through the comparison of reflected amplitudes at

the same depth across all of the raw vertical profiles. The amplitudes of all traces are compared to

the amplitudes of all nearby traces along that profile and between surrounding profiles. This

database of amplitude reflections can then be “sliced” horizontally and displayed to show the

variation in reflection amplitudes at a sequence of depths in the ground. The produced image is a

map that shows changes in amplitudes at a given depth in plan-view. Often when this is done

changes in the subsurface related to disturbances such as the backfilled areas or middens can

become visible.

Slicing of the data generally begins with the reversal of even numbered profiles, to compensate

for the data collection technique. This is needed because the data are collected in transects that

move back and forth to create a grid. Since every other line is collected in the opposite direction,

reversal is necessary prior to mapping the data. Following this step filters are applied to the raw

profiles to remove background noise and other wavelengths that might interfere with the

visibility of the wavelengths reflecting off of buried cultural features. The final step is generating

amplitude slice-maps. Those slice-maps are a series of x,y,z values, with x and y being the

location on the surface within each grid and z being the amplitude of the reflected waves at each

depth in the ground. All of the processing to this point takes place using the GSSI software

RADAN 5.0. Only once the slices are created in RADAN 5.0 can they be exported to a mapping

software, such as Surfer.

From the original .dzt files (raw data), a series of image files were created for cross-referencing

to the amplitude slice-maps that were produced. Two-dimensional reflection profiles are

analyzed to determine validity of the features identified on the amplitude slice-maps. The

reflection profiles show the geometry of the more continuous reflections, which can lend insight

into whether the radar energy is reflecting from a flat layer (seen as a distinct band on profile)

versus a single object or wall (seen as a hyperbola in profile). Using these profiles to confirm or

5

refute ideas about the nature of buried materials seen in the three-dimensional slice-maps,

features of potential cultural significance were delineated.

The GPR data were collected using the GSSI SIR-3000 unit with an attached 400 MHz antenna

(Figure 2). Transects were spaced every 50 cm, which is the approximate width of this antenna.

Transects started in the southwest corner of the grid and were collected in a zig-zag pattern on a

north-south orientation across the grid. The placement of the first transect in the southwest

corner allows for easier processing using RADAN.

Figure 2: GSSI SIR-3000 GPR unit with attached 400 MHz antennae.

GPR data collection works best using a grid format. For the purposes of this survey five separate

grids were set-up surrounding the railroad depot on the eastern, southern, and western sides

(Figure 3). The size of each grid was modified to fit within the area of potential effect (APE). A

total of 1218 square meters were surveyed for this project (Table 1).

Table 1. Summary Information for GPR Grids.

Grid X-length (m) Y-length (m) Area (m2)

1 5 30 150

2 12 4 48

3 5 24 120

4 15 30 450

5 15 30 450

Total 1218

The primary advantage and use of RADAN is its ability to process GPR data in 3D, although it

also has other significant features such as removal of background noise, the application of

different filters, and calculation of radar velocity through the ground. Once a 3D image was

generated in RADAN for each grid, we then created time slices at regular depths and exported

them to Surfer for additional processing. Surfer works very well at manipulating files containing

6

X,Y, and Z coordinates. Once in Surfer, each grid was analyzed individually. For consistency,

each grid was sliced at 20 cm intervals from the surface to approximately 160 cm. In a few cases

where radar readings and field conditions were particularly good, and/or there were targets, we

continued slicing up to 2 m. We could then change color values to amplify high reflectivity

targets. Surfer also allows for multiple time slice images to be displayed side-by-side and stacked

vertically for better interpretive results.

Figure 3. Sketch map of grid layout around the Jesup Railroad Depot.

7

RESULTS AND INTERPRETATIONS

Results from the survey indicate several anomalies that could be associated with Site 9WY93.

Several linear reflections were also identified during this survey and determined to be associated

with buried utilities. An employee with the City of Jesup verified the location of several buried

utilities prior to cutting holes in the asphalt and digging additional shovel test pits beneath the

parking lot. The employee’s information corresponded with utility features visible in the GPR

data.

Data were interpreted using both GPR profiles and amplitude slice-maps. Particular attention

was given to the depths of reflected features. High amplitude reflections that occurred from 0-30

cmbs could represent features that might be impacted by the milling and repaving of the parking

lot. Deeper features, 30+ cmbs, will not be impacted by the current construction plans.

Therefore, even if deeply buried high amplitude reflections indicate features associated with the

Jesup Railroad Depot additional testing may not be recommended as these features will not be

impacted by the rehabilitation project.

Grids 1-3

Grids 1 and 3 were placed on the eastern side of the depot building, while Grid 2 was placed to

the south of the depot building (Figure 3). These three grids were all based upon the same datum

point in the southwest corner of Grid 2. This allowed for all three of the grids to be processed

together in RADAN. In total Grids 1-3 measured 318 square meters. The entire area was paved,

which provided for very good antennae coupling with the ground surface during the survey. Only

a few locations, such as the railroad tracks and places where the pavement had been patched,

caused minimal uncoupling of the antennae with the ground surface.

8

Figure 4: Amplitude Slice-Maps for Grids 1, 2, & 3.

Only one feature, an abandoned portion of a railroad track spur (Feature 1), was visible on the

ground surface. This portion of railroad track was located in the northwest quadrant of Grid 1

and was highly visible in both the GPR amplitude slice-maps (Figure 4) and reflection profiles.

The surface condition of the railroad tracks indicates that any remaining components of the

feature have been encased in concrete. Encasement likely occurred once the portion of track was

out of use and the entire area surrounding the depot was paved for a depot parking and staging

area.

Figure 6

Figure 8

9

Figure 5: GPR profile 2 from Grid 1.

The railroad crossties appear in GPR reflection profile 2 from Grid 1 (Figure 5) as regularly

spaced hyperbolas, which extend from the northern edge of the grid 22 meters to the south.

These hyperbolas are seen in the amplitude slice-maps as evenly spaced lines oriented

approximately east-west. The crossties are especially visible in the slice that averages the

amplitude of reflections between 25-50 cmbs (Figure 6).

Figure 6: Feature 1, railroad tracks visible on the ground surface.

Results from the GPR survey over the railroad track spur indicate that much of the subsurface

structure of the tracks is still intact, but encased in concrete. Crossties can be seen in both the

amplitude slice-maps and reflection profiles. Feature 1, located east of the Jesup Railroad Depot,

is within the project’s area of potential effect. No construction activities are proposed for this

side of the depot as part of the project to rehabilitate the depot and repave the parking lot. Based

upon the track and crosstie encasement in concrete and the current design plans for the

rehabilitation project no additional testing is recommended for this feature.

Crossties

22 meters

N

10

Figure 7: Railroad track spur visible on the ground surface and located within Grid 1.

South of the depot is another paved area. An employee of the City of Jesup indicated that this

area had the potential to house an underground utility line. Two such lines were identified in the

amplitude slice-maps between 0 and 100 cmbs (Figure 8). These lines, annotated in Figure 8,

connect the southern side of the depot with utilities located outside of the survey area.

Figure 8: Linear utility features.

Neither Grid 2 nor Grid 3 contained any apparent features historically associated with the depot.

Utility lines identified in the GPR data are associated with the modern depot as indicated by the

employee of the City of Jesup, their shallow depth, and an associated above ground feature

(Figure 9). Based upon interpretations of the GPR data no additional testing is recommended for

this portion of the parking lot.

Utilities

11

Figure 9: Photograph of Grid 2 facing northwest.

Grids 4 & 5

Grids 4 and 5 were located to the west of the Jesup Railroad Depot building in the main portion

of the parking lot (Figure 3). Both grids measured 30 meters north-south and 15 meters east-west

for a total of 900 square meters. This encompassed almost the entire paved area to the west of the

depot building. However, a narrow section, 5 meters or less in width, adjacent to the building

was not included in either of these grids. Shovel test pits were already dug in this area during the

original Phase I archaeological survey completed by the Consultant. Since the grids were placed

next to one another with a shared datum in the southwest corner of Grid 4 and the northwest

corner of Grid 5 they could be processed together in RADAN.

Figure 10: Parking lot where Grids 4 & 5 were located.

As with Grids 1-3 the entire survey area in Grids 4 and 5 was paved. Good antenna coupling was

facilitated by the relative smoothness of the paved surface. Some sections had been disturbed by

various methods used to patch holes and facilitate repairs in the parking lot (Figure 10). These

Utility feature

12

areas were easy to pull the antenna over and did not have a significant impact on the depth

interpretation for the GPR data.

Figure 11: Amplitude Slice-Maps for Grids 4 and 5.

Several anomalies were identified within Grids 4 and 5, including utility lines, a former depot

entrance, possible old tree locations, and unidentifiable features potentially associated with the

depot or an earlier occupation of the site. Figure 11 shows all of the amplitude slice-maps for the

composite of Grids 4 and 5. Areas of interest are outlined and described in detail below. These

areas are where anomalies were the most apparent. In total 3 anomalies are interpreted based

upon their possible association with site 9WY93. Of these anomalies two are considered to be

potential features associated with the depot and the other anomaly is a water line. As with Grids

1-3 the depth of each anomaly in Grids 4 and 5 is emphasized. Any feature located deeper than

30 cmbs does not have the potential to be impacted by repaving of the parking lot.

Figure 12

Figure 17

Figure 15

13

Figure 12: Feature 2, former depot entrance.

A highly reflective crescent-shaped feature is visible in Grids 4 and 5 and between 0-275 cmbs.

The feature is visible in reflection profiles and amplitude slice-maps from both grids. However,

the geometry of the crescent-shaped feature is more readily visible in the amplitude slice-maps,

outlined in Figure 12 with a solid red line. The GDOT has an archive of aerial photography from

their projects. This archive was searched for photographs that might show changes in the use of

the area surrounding the depot. The earliest aerial photograph available through GDOT for the

City of Jesup was created on October 19, 1959 (Figure 13). A crescent-shaped grassed area

appears in this photograph to the west of the depot building (Figure 13A). This grassed area

indicates that the rectangular parking lot now located to the west of the building was not in use in

1959. Instead a pull-through entrance was used to direct traffic in and out of the depot. There is

no evidence that the American Stick Style depot, which predated the present structure (Caldwell

2001:203), used the same entrance as the pull-through seen in the 1959 aerial photograph.

However, the aerial photograph does indicate that the pull-through was part of the historic depot

built sometime following 1900.

Profile 48

14

Figure 13: Aerial Photograph of a portion of downtown Jesup taken in 1959.

The high amplitude crescent-shaped reflection was possibly created by years of differential water

seepage between the grassed area and the paved pull-through. Profile 48 from Grid 4 shows the

layer just below the ground surface (Figure 14). Because the pull-through layer is located at such

a shallow depth it has likely been consolidated with the paved parking lot placed atop it. A

shovel test pit may indicate a difference in material used to construct the two paved surfaces, but

information on horizontal shape is more readily defined through the use of aerial photography

and geophysical data. Therefore through these methods more is known about this feature than

could be determined through shovel testing or even test excavation units. It remains to be seen

whether or not any differentiation is possible between the paving of the pull-through and that of

the parking lot. Due to the amount of information already gained from aerial photography and

geophysical analysis no additional testing is recommended. Repaving of the parking lot may

impact the pull-through layer. However, this layer has already been impacted by prior paving of

the parking lot and therefore would not be an adverse impact.

A B

15

Figure 14: GPR profile 48 from Grid 4.

Geophysical interpretations of another group of reflections were enhanced through the use of the

1959 aerial photograph. Feature 3 appeared on the northern edge of Grid 4 in amplitude slice-

maps between 150-200 cmbs (Figure 15). The aerial photograph of the City of Jesup also shows

one tree located in approximately the same location (Figure 13B).

Figure 15: Feature 3, possible historic tree location.

In Profiles 43 - 51 from Grid 4 the last 3 meters of each profile show areas where the sandy

subsurface is disturbed (Figure 16). Part of Feature 3 is obscured by a shallower hyperbolic

reflection, described below, located approximately 100 cmbs (Figures 11 & 16). When the tree

was removed from the depot’s landscaping it is unlikely that the entire root mass was also

removed. The organic remnants of the tree would have a high contrast to the natural sandy

subsurface beneath the parking lot. Throughout all the reflection profiles from Grids 4 and 5

Feature 3 appears to be the most distinct from the surrounding soil matrix. Anomalies located in

primarily sandy soils should be visible as high contrast reflections. The overall lack of high

N

42-53

Meters

16

amplitude reflections in the GPR data from Grids 4 and 5 made the area defined as Feature 3

significant.

Figure 16: GPR profile 50 from Grid 4

A water drainage pipe was placed on top of Feature 3 sometime after the reflective surface was

created. The pipe appears in the reflection profiles as a very distinct hyperbola, the apex of which

is located at approximately 100 cmbs (Figure 16). This modern intrusion has likely compromised

the integrity of the reflective surface identified as Feature 3. Although there is no visual

confirmation of the feature, it is outside of the project’s vertical area of potential effect.

Therefore no additional testing is recommended for this feature.

Figure 17: Water line

As described above a water line was intrusive in both Grids 4 and 5. The water line is visible in

almost all of the amplitude slice-maps as linear reflective surfaces. These surfaces are marked in

Figure 17 with a black line and are located along the northern edge of Grid 4, the eastern edge of

Grids 4 and 5, and running east-west at approximately 23 m north in Grid 5 (Figure 11 & 16).

Since these reflections were identified as water utility lines no additional testing is recommended

for these anomalies.

N

27-30

Meters

17

CONCLUSIONS AND RECOMMENDATIONS

A geophysical survey using ground penetrating radar was incorporated into the analysis of

9WY93, the Jesup Railroad Depot, to ensure that potential impacts to any features associated

with the site, but buried under a paved parking lot, were assessed. Five GPR grids were placed

around the depot building almost entirely covering the paved surfaces. Results from this survey

identified five anomalies, three of which are proposed to be associated with the depot (Figure

18).

Figure 18: Location of features visible in the GPR data.

Two of the anomalies identified were associated with modern utility work at the site. Utility lines

were visible in both the amplitude slice-maps and the reflection profiles as linear high amplitude

reflections and distinct hyperbolas. A worker for the City of Jesup identified all of these utilities

prior to the survey. Although these anomalies are not associated with site 9WY93 they are

outside of the project’s vertical area of potential effect, 30+ cmbs or deeper.

18

Feature 1, a railroad track spur, was visible on the ground surface and easily associated with the

depot. The tracks and their crossties were visible in both the amplitude slice-maps and reflection

profiles. Both above-ground and subsurface evidence indicate that the tracks have been encased

in concrete as part of paving the parking lot in the past. As the integrity of this feature has

already been impacted by past paving and the feature is located outside of the current project’s

area of potential effect, no additional testing is recommended for the railroad track spur feature.

The second feature was located in Grids 4 and 5 and was visible as a crescent-shaped highly

reflective layer in the amplitude slice-maps and reflection profiles from 0-275 cmbs. A former

paved pull-through entrance was identified in an aerial photograph of downtown Jesup taken in

1959. The aerial photograph confirmed that the crescent-shaped Feature 2 was associated with

depot at least 49 years ago. This feature is however located just below the ground surface and has

been paved over by the current parking lot. Additional testing of this feature is not likely to yield

any additional information than what has already been discussed. Therefore no additional testing

of this feature is recommended for the pull-through entrance.

Feature 3 was located in Grid 4 and is the most ephemeral of the three features. At a depth of

approximately 150 - 200 cmbs a disturbance can be seen in the amplitude slice-maps and the

reflection profiles. Based upon aerial photography evidence this feature could be associated with

a tree that was part of the depot’s landscaping in 1959. The root mass from the tree may not have

been removed with the tree thus leaving behind organic remains in sandy soil, which would

create a strong contrast for electromagnetic energy to be reflected off of. This feature is located

outside of the project’s vertical area of potential effect and therefore does not warrant additional

testing.

Based upon the geophysical data collected during July 2008, several features were identified that

are potentially associated with the Jesup Railroad Depot, 9WY93. However, all of these features

have either already been negatively impacted by paving of the parking lot or are outside of the

project’s area of potential effect. Therefore no additional testing is recommended for the three

features identified during this survey.

19

REFERENCES CITED

Owens, Daphne L.

2008 An Archaeological Survey in Anticipation of the Rehabilitation of the Jesup Railroad

Depot, Wayne County, Georgia. Cypress Cultural Consultants, LLC. Submitted to the

Georgia Department of Transportation, Project CSMSL-0008-00(691), PI# 0008691.

Copies available from the Georgia Department of Transportation.

Caldwell, Wilber W.

2001 The Courthouse and the Depot: The Architecture of Hope in the Age of Despair. Mercer

University Press, Macon, Georgia.

Conyers, Lawrence B.

2006 Innovative Ground-penetrating Radar Methods for Archaeological Mapping.

Archaeological Prospection 13:137-139.

2004 Ground-penetrating Radar for Archaeology. Altamira Press, Walnut Creek, California.

Soil Survey Staff

2008 Natural Resources Conservation Service, United States Department of Agriculture.

Official Soil Series Descriptions electronic document,

http://soils.usda.gov/technical/classification/osd/index.html, Accessed August 21, 2008.