Archaeogeophysics and Archaeology at a Caddo Mound Center in Southwestern Arkansas: The Tom Jones Site (3HE40) at Grandview Ranch

By Jami J. Lockhart and Frank F. Schambach
Arkansas Archeological Survey

Figure 1a. General location of Grandview
Figure 1a. General location of Grandview

The area known as Grandview Ranch is located in Hempstead County near Hope, Arkansas, in the southwestern part of the state. This 4885-acre property, originally the antebellum Grandview Plantation, is now the Grandview Prairie Wildlife Management Area, owned by the state of Arkansas and managed by the Arkansas Game and Fish Commission. The property had been protected from development and from looters by its previous owners. As a consequence, numerous historic and prehistoric archaeological sites within the boundaries of Grandview Ranch remain largely undisturbed and many are in pristine condition.

Figure 1b. Central mound at the Tom Jones Site
Figure 1b. Central mound at the Tom Jones Site

One of the most important prehistoric sites on the property is the Tom Jones site, Arkansas site number 3HE40 (Figures 1a and 1b). Beginning in 2001, and continuing in 2002, excavations at the Tom Jones site were carried out by the Arkansas Archeological Survey and members of the Arkansas Archeological Society under the direction of Dr. Frank Schambach, the Survey Station Archeologist at Southern Arkansas University. This ongoing research project also receives support from the Arkansas Game and Fish Commission, whose responsibilities to the property include the obligation to manage and protect its archaeological resources.

As part of the archaeological research design, selected parts of the Tom Jones site were explored using archaeogeophysical equipment for near-surface prospection. Archaeogeophysics in conjunction with pinpointed excavation and analysis provides our best chance to discover the constructed and even the conceptualized components of cultural landscapes — landscapes built by people and also invested by them with often profound cultural meaning. The range of technologies employed, together with the simultaneous excavations that allowed us to "ground-truth" the computer-generated imagery, made this project the first full-scale test of geophysical remote sensing for archaeological research in Arkansas, and among the first in the Southeast region. The archaeogeophysical aspect of the Grandview research is directed by Jami J. Lockhart.

The Tom Jones site is a Caddo mound center consisting of a temple mound and at least five outlying mounds. Based on the evidence gathered so far, it appears that the Tom Jones site was occupied until approximately 500 years ago. Occupation probably reached its zenith during the latter part of the three centuries bracketed by A.D. 1200 and 1500. Chronometric dating of features is currently underway.

Grandview Ranch is located within the archeogeographic province of the Trans-Mississippi South, which is characterized as a marginal southeastern woodland environment. The area contains bottomland hardwood forests and prairie enclaves. The Tom Jones site itself is located at the edge of one of these prairie enclaves.

Figure 2. Caddo Subregions within the Central Caddo Area
Figure 2. Caddo Subregions within the Central Caddo Area

The site is also located very near the conjunction of three Caddo subregions within the Central Caddo Region (Figure 2). The Great Bend Caddo subregion encompasses the Red River Valley in southwestern Arkansas, northeastern Texas, and northwestern Louisiana. On its northern extent, this subregion shares a non-isomorphic boundary with both the Little River and the Little Missouri subregions. These Caddo subregions are composed of overlapping natural systems and subtle distinctions of cultural adaptation.

A large number of Caddo ceremonial centers are scattered along the major streams and tributaries in the Central Caddo Region. The Tom Jones site at Grandview is distinctive in several ways. Of 103 mound sites known from this region, only four are located on the geologic classification known as Saratoga Chalk. Tom Jones is one of these four. The site is on high ground, at an unusual distance from a reliable watercourse. The nearest creek, Terre Rouge Creek, is seasonal and is almost a kilometer away. The south fork of Ozan Creek is 2 km away. Somewhat nearer, approximately half a kilometer from the site, is a spring with an unusual bell-shaped cistern of impressive depth and a large surface aperture. This spring flows even in dry periods, and often overflows the ground in wet weather. It is possible that this spring was cut (or enlarged) into the underlying limestone during prehistory, which would make it a unique feature indeed and worthy of a separate paper.

All recognized time periods of human occupation in North America are represented in the archaeology of the Caddo cultural area. Domed burial mounds gave way to flat-topped ceremonial mounds sometime during the Late Woodland period, and settlement patterns shifted from villages of up to 10 acres in size to sparsely populated ceremonial centers supported by small, dispersed farmsteads. The latter pattern is true for the protohistoric period too, according to the limited early ethnographic evidence.

One valuable source of information on Caddo settlement patterns comes from the Teran Map, compiled during a Spanish expedition in the area during 1691 and 1692 (Figure 3). This map depicts a dispersed community made up of 25 clusters of buildings, including 23 farmsteads, arranged along the banks of the Red River with two oxbow lakes. A ceremonial center with a mound and temple is shown at the western margin.

Figure 3. The Teran Map (ca. 1691). Image courtesy of the J.T. Bryan Map Collection, The Center for American History, University of Texas at Austin.
Figure 3. The Teran Map (ca. 1691)

The sociopolitical and ceremonial system of the Caddo was hierarchical. The paramount leadership position was occupied by a xenesi, in whom all sacred and secular power was focused. This individual probably resided at the temple complex on the margin of the community (or communities) and maintained the sacred temple fire. In addition to political duties such as presiding over the ritual calendar, the xenesi communicated with the supernatural realm. His power inspired intricate procedures of deference and obligation — for example, he and his immediate underlings were supplied with provisions and did not have to engage in economic activities on their own behalf. Sources suggest that other important ritual buildings were probably located near the temple complex.

Figure 4. Archaeogeophysics: Non-invasive methods for analysis and delineation of subsurface archaeological or cultural features (Conyers and Goodman, 1997). From left to right: Electical Resistance, Electromagnetic Conductivity and Magnetic Susceptibility, Ground Penetrating Radar, Fluxgate Gradiometry.
Figure 4. Electical Resistance Figure 4. Electromagnetic Conductivity and Magnetic Susceptibility Figure 4. Ground Penetrating Radar Figure 4. Fluxgate Gradiometer

The geophysical explorations at Grandview Ranch can be integrated into our existing knowledge base of Caddo area archaeology and ethnography. This study brings a particular set of technological tools to the study of Caddo spatial organization, and attempts to understand what that organization meant (Figure 4). Potential exists for research at two scales — the intrasite scale within the Tom Jones site area (3HE40), and the intersite scale, which looks at the larger cultural landscape of which this site is only one element, albeit an important one. This paper reports some of our conclusions at the intrasite scale of research, focusing on how the Tom Jones site functioned as a whole. Topics that may be addressed from this perspective include the site's physical layout, its population, characteristics of the immediate environment, and archaeological features within the site that define its overall function and tell us something about Caddo cultural organization, world view, and lifeways.

Figure 5. Topography & Geophysical Grids. CLICK ON IMAGE TO ENLARGE
Figure 5. Topography & Geophysical Grids

An integral component of this intrasite portion of the study entails large-scale contiguous coverage of the site using a variety of geophysical survey equipment (Figure 5). To date, fifteen 20 x 20 m geophysical grid units have been surveyed using electrical resistance, electromagnetic conductivity, magnetic susceptibility, and magnetometry (gradiometry). Initial results appear very favorable both for the location and identification of buried structures and other features using these techniques.

In the remainder of this paper we will look in detail at the results and interpretations in four specific locations on the Tom Jones site. First is an area just to the west of the large flat-topped temple mound (Figure 6). The magnetometry/gradiometry results for seven contiguous 20 x 20 m squares in this area show anomalies that we interpreted as at least five subsurface Caddo structures, some more heavily burned than others.

For a closer look at just one of the 20 x 20 m squares in this group, compare the imagery from all four techniques — magnetic susceptibility, gradiometry, electrical resistance, and electromagnetic conductivity — in geophysical grid unit 7 (Figure 7). Each technique measures different physical properties, but all four indicate similar anomalies. The signature in the lower left of each image was interpreted as a structure with massive burning. The anomaly in the upper center — most noticeable in the magnetic susceptibility and gradiometry — was interpreted as the wall line of another structure with a central hearth.

Figure 6 (left) - Grandview (3HE40) Gradiometry, grids 5,6,7,8,9,10 and 11. Figure 7 (right) - Grid 7. Red lines indicate anomalies and data trends. CLICK ON IMAGES TO ENLARGE
Figure 6. Gradiometry, grids 5,6,7,8,9,10 and 11 Figure 7. Grid 7

To test these interpretations, excavation units were "pinpointed" over the anomalies by locating georeferenced points within the imagery and using a Total Station transit to position them precisely on the ground. The excavations revealed that there was indeed a burned prehistoric structure in grid unit 7. Figure 8 shows the massive concentration of fired clay or burned daub that was responsible for the large magnetic readings in the geophysical image. A number of ceramic vessels were associated with this structure, including a large jar upended over a deer scapula (Figure 9).

Features associated with the burned prehistoric structure in grid unit 7. Figure 8 (left) - fired clay feature. Figure 9 (right) - ceramic jar and deer scapula. CLICK ON IMAGES TO ENLARGE
Figure 8. Fired clay feature Figure 9. Jar and deer scapula

Figure 10 (left) Grid 7 anamoly, and Figure 11 showing the location of Grids 1-4. CLICK ON IMAGES TO ENLARGE
Figure 10. Grid 7 anamoly Figure 11. Location of Grids 1-4

Excavations also revealed post molds in the interpreted wall line anomaly in the upper center portion of grid unit 7. Another pinpointed excavation unit confirmed the location of a hearth in this area as well (Figure 10).

The second example is in another part of the site (Figure 11), in geophysical units that are some 250 to 300 meters away from the large mound (which gives an indication of the overall size of the site). The anomalies in this area were also interpreted as buried structures. The excavation units were aligned to bisect only one of the anomalies — the one marked "verified structure" in Figure 12.

Figure 12 (left) - Electrical Resistance, grids 1-4 showing the location of the verified structure (grid 1), a suspected structure (grid 2) and other anomalies (grid 4). Figure 13 (right) shows the clearly defined post molds found in grid 1. CLICK ON IMAGES TO ENLARGE
Figure 12 . Electrical Resistance, grids 1-4 Figure 13. Post molds in grid 1

There were again large clusters of burned daub, and a series of post molds along a wall line. The unusual geology of Saratoga Chalk mentioned above makes for a striking contrast between the post molds and surrounding soil matrix (Figure 13). Some of the artifacts associated with this structure are an unusual star-shaped ceramic pipe, charred beams, corn kernels, and beans.

Figure 14 - Grid 12. CLICK IMAGE TO ENLARGE
Figure 14. Grid 12

The third area is nearly half a kilometer away, in geophysical grid unit 12 (Figure 14). The imagery in this area also showed anomalies that proved,upon excavation, to be a prehistoric structure with many features and artifacts, including prehistoric graves dug through the floor of the structure. Excavations on these features were closed when the graves were encountered. There is a very close correspondence here between the imagery produced by two different devices — magnetic susceptibility and gradiometry (Figure 15).

Figure 15 - Grid 12. CLICK ON IMAGE TO ENLARGE
Figure 15. Grid 12 - Imagery produced by two different devices.

Finally, anomalies in geophysical unit 5 — again, close to the large mound — we strongly suspect to represent another buried structure surrounded by smaller features (Figure 16). This area has not yet been excavated, and may not be. It is similar in size, shape, and signatures to the other geophysical anomalies that have already been verified as buried prehistoric structures.

Another view of this last anomaly using a shaded relief visualization technique shows the orientation of the structure and other details (Figure 17). The protuberance at the lower right might be interpreted as the structure's entrance. If correct, it would have been facing the large mound. Figure 18 allows us to imagine the scene presented to the occupant of this house from his front door.

Figure 16 (left) - Grid 5 - Multiple technologies indicate a buried structure surrounded by smaller features. Figure 17 (right) - Shaded Relief Visualization of magnetometry data in geophysical grid 5. CLICK ON IMAGES TO ENLARGE
Figure 16. Grid 5 - Multiple technologies indicate a buried structure surrounded by smaller features Figure 17. Shaded Relief Visualization of magnetometry data in grid 5

Were the people that occupied the structures at this Caddo ceremonial center the social and religious elite? Of all the artifacts recovered during our limited and focused excavations, very few reflect lithic tool processing, or tool-making of any sort. This suggests the possibility that their lives were oriented to other sorts of activities. Were their meals brought to them? Were there more structures and more people living nearby, perhaps in the plaza area in front of the mound? Or will the model suggested by the Teran Map, with a ceremonial mound on the periphery of dispersed farmsteads, eventually be proved accurate? Geophysical survey over larger areas of the Tom Jones site and at similar sites should help answer these and other important questions.

Figure 18. View of the mound from Grid 5 (3HE40)
Figure 18. View of the mound from Grid 5 (3HE40)

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