Stallings Island Revisited: Modern Investigation of Stratigraphy and Chronology

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Title:
Stallings Island Revisited: Modern Investigation of Stratigraphy and Chronology
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Technical report
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Sassaman, Kenneth E.
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Laboratory of Southeastern Archaeology, Department of Anthropology, University of Florida
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Gainesville, Fla.
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Abstract:
Stallings Island (9CB1) is a large shell-midden site in the Savannah River near Augusta, Georgia, that figures prominently in archaeological perspectives on the origins of pottery and cultural complexity among hunter-gatherer societies of the American Southeast. Despite repeated investigations since the last century, Stallings Island was not securely dated with absolute chronometric methods. National Geographic funds supported an expedition to the site in 1999 to reopen a 1929 excavation for purposes of detailed stratigraphic mapping and radiocarbon sampling. The main trench of this early dig was located, but virtually none of the midden in the profiles of these units remained intact. Fortunately, many undisturbed pit features were preserved in the residual clay beneath the midden. Strategy was shifted to seek out pit features in the old excavation block, and in some of the hundreds of looters’ pits at the site. Nearly all locations produced intact features filled with freshwater shell, charcoal, vertebrate remains, and artifacts. In addition, an area of the site heretofore regarded as geologically disturbed proved to contain over two meters of stratified shell midden. All told, dozens of pit features and a column from the deep shell strata provided ample opportunity for radiocarbon dating. Seventeen assays returned thus far not only enable Stallings Island to be situated firmly in the emerging details of regional chronology, but extend back by several centuries the onset of intensive habitation and shellfishing in the middle Savannah River valley.
Funding:
Report submitted to the National Geographic Society in partial fulfillment of Grant #6411-99, December 10, 1999

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Stallings Island Revisited: Modern Invest igation of Stratigraphy and Chronology Kenneth E. Sassaman Department of Anthropology University of Florida Gainesville, FL 32611 Report submitted to the National Geographic Society in partial fulfillment of Grant #6411-99, December 10, 1999 Laboratory of Southeastern Archaeology Technical Report 2 Abstract Stallings Island (9CB1) is a large shell-midde n site in the Savannah River near Augusta, Georgia, that figures prominently in archaeologi cal perspectives on the origins of pottery and cultural complexity among hunter-gatherer societies of the American Southeast. Despite repeated investigations since the last century, Stallings Island was not securely dated with absolute chronometric methods. National Geographic funds s upported an expedition to the site in 1999 to reopen a 1929 excavation for purposes of deta iled stratigraphic mapping and radiocarbon sampling. The main trench of this early dig was located, but virtually none of the midden in the profiles of these units remained intact. Fortunately, many undisturbed pit features were preserved in the residual clay beneath the midden. Strategy was shifted to seek out pit features in the old excavation block, and in some of the hundreds of l ooters pits at the site. Nearly all locations produced intact features filled with freshwater she ll, charcoal, vertebrate remains, and artifacts. In addition, an area of the site heretofore rega rded as geologically disturbed proved to contain over two meters of stratified shell midden. All told, dozens of pit features and a column from the deep shell strata provided ample opportunity fo r radiocarbon dating. Seventeen assays returned thus far not only enable Stallings Island to be s ituated firmly in the emerging details of regional chronology, but extend back by several centuries th e onset of intensive habitation and shellfishing in the middle Savannah River valley. Stallings Island (9CB1) is a National Landmark site in the middle Savannah River valley of Georgia that has been the subject of repeated archaeologi cal investigati ons since the 1850s. As the namesake for the oldest potte ry in North America, Stallings Island has figured prominently in the development of knowledge about increasing settlement permanence and social complexity in the prehistoric Southeast. Despite its central importance to prehistory, knowledge about Stallings Island has been more mythical than factual. Of the many professional investig ations of the site (Bullen and Greene 1970; Crusoe and DePratter 1976; Fairbanks 1942), only the 1929 Peabody Museum expedition was reported in detail (Claflin 1931). Naturally, a report of work conducted 70 years ago cannot possibly satisfy all modern resear ch needs. The Peabody investigators emphasized the recovery of ar tifacts and skeletal remains, and whereas they conducted stratigraphic mapping and featur e excavation, a lack of inde pendent dating prevented a detailed reconstruction of site forma tion, occupational sequence, and community patterning. Since 1991 the Stallings Archaeologi cal Project has undertaken field investigations at several othe r Stallings-period sites in the middle Savannah River valley. 1

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All such investigations were prompted by loot ing activities, as the shell-rich deposits of these sites have preserved orga nic artifacts, such as carved bone pins, that bring premium prices on the antiquities market. Despite th e damage from looters, these sites still preserved intact subsurface feat ures, many with datable organics and diagnostic artifacts. One result of this work has been an incr easingly detailed chr onology of the cultural developments leading to classic Stallings Culture of 3800-3500 radioc arbon years before present (rcybp) (Sassaman 1998). As stratigraphic work at St allings Island demonstrated 70 years ago, classic Stallings Culture was preceded by a preceramic culture known today as the Mill Branch phase of the Late Archaic period (Elliott et al. 1994:371). Dating from about 4200-3800 rcybp, the Mill Branch phas e represents much more than a local ancestor or predecessor to St allings Culture. A growi ng body of evidence suggests strongly that groups of Mill Branch affinit y, with ancestry in the middle Savannah region extending back at least five centuries, coex isted with early Stallings communities for upwards of 200 years. These latter communities have histor ies of coastal settlement dating from about 4600 rcybp, but they began to make seasonal use of middle Savannah riverine sites after about 4000 rcybp. The hypothe sis that arises from these new data is that the emergence of classic Stallings Culture in the middle Savannah at about 3800 rcybp was a sociopolitical consequence of inte ractions between ethni cally distinct Mill Branch and early Stallings communities. As the regional chronology for Stallings genesis developed from investigations elsewhere, the type site, Stallings Island, ha d little to offer. Three radiocarbon dates obtained from samples collected by Bruce Greene (Williams 1968:331) generally agree with the rough details of re gional chronology, but they were hardly sufficient to situate the various components of this complex si te in the emerging details of Stallings chronology. The opportunity to remedy this situate came in 1998, when the Archaeological Conservancy acquired Stal lings Island from the land owner, who stipulated in the transfer that the site be not only protecte d from further looting, but also availed to scientific investigation. Knowing how severely Stallings Island ha d already been impacted by previous excavations and more recent looting, I was reluctant to initiate new excavations of sufficient scope to characterize the intern al chronology of the site. At over 5000 m2 in extent and as much as 3 m thick, the midden de posits that constitute the core of Stallings Island would require extensive digging to ensu re adequate sampling. In lieu of new excavations, I proposed that the 1929 excavati ons of the Peabody be reopened to expose one of the profiles that bisected the midden. Previous work exposed strata with intervening layers of shell and loam resti ng on residual clay generally 1.0 to 1.5 m below the surface across most of the deposit. Given our recent success at dating freshwater clam shell from other Stallings sites (Sassama n 1998), I proposed that we simply collect samples of shell from portions of intact prof ile to establish, at the minimum, the range of time represented by episodes of shellfish discard. The strategy then was to relocate the profile of the 210-ft-l ong Trench 2dug in 1929 under the direction of Mr. And Mrs. C. B. Cosgrovemap it in detail, and collect at least 24 samples for radiocarbon dating. A recent topographic map of the site with a 2-ft 2

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contour interval showed a su rface depression in the general vicinity of the Cosgroves block excavation, which was bordered on its nor th edge by Trench 2. Three test units were opened along the northern edge of this depression, in what presumably was the western half of Cosgroves unit. None of the units intercepted decidedly intact midden deposits, but exposed in the floor of Test Unit 1 was a trench that penetrated some 55 cm into basal clay (Figure 1). Nothing in th e 1931 report suggests that the Cosgroves crew dug into basal clays in this part of the site, so we were skeptical that this feature related to their activity. However, we later exposed the trench in Test Unit 6, just to the west of Unit 1 (Figure 1). Projected across the entire site, the alignment of these two exposures conforms rather well with the topographic depr ession, particularly as it appears in the 10cm contour map we generated from about 1400 laser transit readings (Figure 2). Having located Trench 2 we were at a loss for how to proceed, for none of the midden profile above the clay was preserved in any of the test units opened thus far. Indeed, looting at the site was far worse th an we expected. As weedy vegetation was cleared from the surface it became apparent that the entire midden was impacted by illicit digging. Nearly 200 individual looters pits were mapped in the core of the midden (Figure 3); as many more are located along the slopping fringes of the mound. Certainly portions of the midde n remain intact in isolated places across the site, but we had little hope of locating su fficiently preserved midden along the Trench 2 profile to warrant the effort it would take to uncover the entire 210ft long exposure. Fortunately, our initial test units uncover ed something we were not prepared to see but which proved to fulfill our needs for in ternal chronology. In all places where we exposed the clay floor of the Cosgroves block excavation we observed the outlines of pit features. The Cosgroves located and excavated 110 such features, as well as hearths and human burials, and we found clear evidence of on es they had worked. However, we also located pits they overlooked, such as the one bi sected by the trench fill in Figure 1. Like those found by the Cosgroves, unexcavated pits we encountered penetrated as much as 120 cm into the basal clay. They typically contained an organic-rich clay loam with shell, charcoal, abundant vert ebrate bone, and numerous dia gnostic artifacts. Here then was a resource we did not expect to have: a rich assemblage of well-preserved time capsules in the very location excavated by the Cosgroves. What is more, stains of backfilled features in their excavation block coul d be correlated with the published locations, so we were able to overlay the Cosgroves excavation plan on to our modern map despite the lack of a datum from 1929. Rather than put all our effo rts into the redigging of Co sgroves block, we took the opportunity to open up several looters pits to explore the potentia l for preserved midden and submidden features in othe r portions of the site. A to tal of six such pits were investigated with five 2 x 2-m and one 1 x 2m units. The procedure in each case was to orient the test unit so that one edge would al ign roughly with the wall of the looters pit, thereby providing at least one good profile of the midden from surface to basal clay. In all but one unit in the core of the site, the entire profile consisted of reworked midden deposits. Still, in all but one case, the submi dden clay preserved evidence for intact pit features. All told, 54 pit features were located, mapped, and excavated in the 51 m2 of 3

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Figure 1. Views of excavation units exposing portions of the Cosgroves 1929 Trench 2. Left: Grid south profile of Test Unit 1, showing cross-section of Cosgroves Trench 2 where it cut into basal clay. Higher shelf of clay to west (right) of trench represents the undisturbed basal stratum. Intact midden above this stratum was not observed. Right: Close-up view of Trench 2 backfill. Note that the recent age of this feature is apparent in the sharp contrast between clay and organic fill. Note also the characteristically mottled appearance of trench fill. Inside margin of Cosgrove Trench 2 Planview of Test Unit 6 at contact with clay, showing several pit features, postholes, looters backfill, and backfilled Cosgroves Trench 2. Facing Grid East. 4

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test units in looters pits a nd the Cosgroves block combined. A sample of the features is provided in Figure 3. Given the rich organic fill and associated artifacts of most of these features, it goes without saying that they more than fulfilled our needs for developing an internal chronology fo r Stallings Island. One additional surprise awaited us in the te sting of looters pits. Down the slope of the east side of the mound was an especia lly large and deep loot ers pit (ca. 5 m in diameter) that exposed shell de posits at least 2.5 m deep. Th is was the area first tested by the Cosgroves in 1929. In his report of this work, Claflin (1931:5) in terpreted the profile as midden fill that was eroded from upslope by floodwaters and redeposited in an old flood chute. Clearly the eastern margin of the mound had suffered severe erosion from floods of the late 1920s (Claflin 1931:2), so I never thought to questioned Claflins assessment of these deep deposits. However, as we began to expose a profile in this large looters pit (LP81) it became apparent that the upper meter was in fact redeposited fill (flood or looter), but that th e lower two meters reflected in tact shell midden (Figure 4). Once we recognized this fact, a pedestal roughly 1 x 1 m in si ze was left standing in the northeast corner of the unit and then re moved in natural levels for 1/8-inch waterscreening and flotation sampling. Devoid of pottery but rich in shell, charcoal, firecracked rock and soapstone cooking stones, th is column provided additional materials for dating, along with a variety of subs istence and paleoecological data. Radiocarbon Assays With the full recovery of fill from dozens of large pit features and a shell column, this project ended up with much more than it bargained for. National Geographic sponsorship, however, was for the express purpo se of obtaining samples for dating, so I restrict further discussion in this short re port to the results an d interpretation of 17 radiocarbon assays obtained thus far. Table 1 provides data on each of the a ssays, subdivided by the three major phases of occupation at the site and a residual category. The resu lts are very gratifying. The classic Stallings component of the site is securely dated from 3800-3500 rcybp with five assay on samples from four pit features, ea ch containing the dia gnostic drag-and-jab punctate fiber-tempered pottery. The oldest date in this set is the single assay derived from freshwater clamshell from Feature 17 (Beta-133185). Previous efforts at dating paired samples of charcoal and shell from the nearby Mims Point site (38ED9) returned consistently comparable results at onesigma (Sassaman 1998), suggesting that any reservoir effect on shellfish in the area is virtually negligible. The three paired samples analyzed in this effort (F. 17, F.42, and LP81-VI) returned less satisfying results, although all but one pair (LP81VI) are statistically indisti nguishable at the two-sigma range. Thus, freshwater shell dating in th e middle Savannah conti nues to be relatively reliable. Charcoal was the preferred material when samples allowed, but shell was in fact used to obtain nine of the 17 assays. 6

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Figure 3. Examples of pit features dug into basal clay, sectioned for profiling. The Mill Branch phase component at St allings Island was dated to roughly 42004100 rcybp by samples from three features and th e upper shell strata of LP81. All five assays overlap at one-sigma. Not all of th ese contexts produced definitive Mill Branch artifacts, but they each provided circumstan tial evidence for the phase (predominance of metavolcanic flakes, soapstone, lack of pottery ). The surprise here is the association between Mill Branch and large quantities of sh ellfish remains. Prior work at Stallings Island suggested that intensive shellfis hing accompanied the introduction of pottery during classic Stallings times (i.e., post 3800 B.P. ). Clearly this was not the case. The accumulations evident in LP81 suggest that the relative use of shellfish was misinterpreted due to sampling bias: previous efforts focused only in the core of the midden (i.e., the habitation area), where Stal lings households discarded shellfish remains in large pits, whereas their preceramic predec essors did not. The LP81 profile shows that preceramic Mill Branch inhabitants harvested and ate freshwater shellfish intensively, throwing the remains over the sides of the mound into an area heretofore interpreted as flood-eroded and redeposited fill. 7

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The basal strata of the shell column of LP81 places the onset of midden accumulation at about 4400-4300 rcybp, and perhaps a few centuries earlier. This time frame coincides with the Paris Island phase, defined largely through excavations of sites in the upper Savannah River valley (Wood et al. 1986; see Elliott et al. 1994:370). Neither of the two Stallings Island features yielding Paris Island-age assays (F. 29 and 42) included diagnostic artifacts, but they were devoid of potter y. Irrespective of artifact associations, the Paris Island-age assays fr om LP81 are supported by their stratigraphic position at the base of the deposit. Again, pottery was completely absent throughout the LP81 shell column. 8

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Table 1. Data on Radiocarbon Assays from Features and Shell Column of Looter Pit 81 (LP81), Stallings Island (9CB1), Columbia County, Georgia. Classic Stallings Measured 13C/12C Conventional 2-Sigma Context Lab Number Material C14 Age (BP) Ratio (o/oo) C14 Age (BP) Cal. (BP) F. 10 Beta-134458 charcoal 3510 70 -25.0 3510 70 3970-3620 F. 17III Beta-133184 charcoal 3580 60 -27.7 3530 60 3970-3650 F. 16 Beta-134459 charcoal 3550 70 -25.4 3540 70 3985-3645 F. 2 Beta-134456 charcoal 3680 60 -25.4 3670 60 4155-3845 F. 17III Beta-133185 shell 3490 70 -9.3 3740 70 4290-3895 Mill Branch F. 36 Beta-134463 shell 3830 70 -9.7 4080 70 4830-4410 F. 24 Beta-134460 charcoal 4100 60 -25.7 4090 60 4825-4425 LP81-Ib Beta-134464 shell 3860 70 -7.8 4140 70 4845-4435 F. 33 Beta-134462 shell 3940 70 -8.7 4200 70 4865-4530 LP81-5-8a Beta-134466 shell 3940 60 -8.5 4210 60 4860-4555 Pre-Mill Branch LP81-VI Beta-133189 shell 4100 70 -8.8 4360 70 5275-5175 5070-4830 LP81-V Beta-134465 shell 4100 60 -8.5 4370 70 5280-5165 5130-5105 5075-4830 F. 29 Beta-134461 charcoal 4400 70 -25.4 4390 70 5290-4835 F. 42 Beta-133186 charcoal 4450 70 -26.3 4430 60 5295-4855 F. 42 Beta-133187 shell 4340 70 -9.5 4590 70 5470-5045 LP81-VI Beta-133188 charcoal 4840 70 -25.7 4830 70 5670-5455 5380-5335 Ambiguous F. 7/8 Beta-134457 shell 3650 70 -9.2 3910 70 4525-4145 Putting the Stallings Island assays into re gional context, seve ral significant new findings can be advanced (Figure 5). First, the antiquity of intensive riverine settlement and shellfishing in the Middle Savannah can be pushed back some two to three centuries. The cultural affiliation of this early phase ca nnot be specified presently, although it is all but certain that it reflects lineal ancestry of those communities comprising the Mill Branch phase. Second, dates for Mill Branch occupation at Stallings Island corroborate those from the nearby Ed Marshall site, th e only other riverine settlement dated radiometrically. Together the Mill Branch components at Ed Marshall and Stallings Island constitute intensive ri verine occupations dating fr om 4200-4000 rcybp; the only other dated contexts for Mill Branch in th e Middle Savannah region come from two sites in the interriverine uplands: Hitchcock Woods and the Mill Branch type site, both dating to the 4000-3800 rcybp interval. Whereas the lack of riverine Mill Branch components dating to this latter aspect of the phase mi ght be attributed to sample error alone, the existence of early Stallings components spanning this interval at th ree riverine (or riveradjacent) sites (Victor Mills, Uchee Creek, and Ed Marshall) renders this prospect less likely. Thus, the co-existence of Mill Branch and early Stallings communities from ca. 4000-3800 rcybp is becoming firmly es tablished. In this regar d, the absence of an early Stallings component at Stallings Island is conspicuous. Previous investigations of the 9

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island noted the occu rrence of plain fiber-tempered pottery (Bullen and Greene 1970), one of the hallmarks of early Stallings mate rial culture. However, the truly defining characteristic of early Stallings pottery is the thickened or flange d lips of plain, basinshaped vessels (because late r, decorated pottery involves the use of zoned motifs that leave large portions of ve ssels undecorated, plain body sher ds alone are not terribly diagnostic). Such forms were exceedingly ra re in the hundreds of rim sherds recovered in this project. Granted, other parts of the Stallings Island site may very well hold evidence for occupations duri ng this early ceramic phase Finally, the five assays obtained from features with classic Stallings pottery conform generally with dates from other cla ssic Stallings components in the region. All five dates overlap at two sigma (3600-3650 rc ybp), matching the statistical range of assays from the well-dated Mims Point site. However, the tight cl uster of three dates from separate, well-defined feat ures at Stallings Is land suggests that th e classic Stallings component actually spans the last few decades of occupation in the region (ca. 3510-3540 rcybp). Riverine sites in the middle Sava nnah are completely abandoned after about 3500 rcybp and would not be again be occupied in any signifi cant fashion for centuries, long after Stallings Culture dissolved. At the time of this writing, several othe r samples from Stallings Island are being prepared for radiocarbon analysis One goal of this final effort is to bolste r the dating of from the shell column of LP81 to determine whether it represents a continuous sequence spanning two or more centuries, or discrete ep isodes of rapid deposit ion at either end of this time span. The second goal is to bol ster the dating of th e classic Stallings component(s) to determine whether they i ndeed represent occupations on the eve of regional abandonment, or an array of occupa tion spanning the entire 200-300-year history of classic Stallings Culture. Conclusion The National Geographic-sponsored expediti on to Stallings Island was a complete success. Although the initial goal of locating and sampling one of the profiles of the 1929 excavation was not realized, the discovery of intact features throughout the site was welcomed consolation. In addition, we locat ed deeply stratified midden deposits in a portion of the site long regarded as dest royed. Together the midden and features provided ample opportunity for radiometric dating in contexts rich in diagnostic artifacts, subsistence remains, and other data classes. Detailed mapping of the core of the site and subsurface testing will aid the Archaeological Co nservancy in its effort to stabilize and preserve Stallings Island. Our work demons trated unequivocally that the site has much untapped potential for scientif ic investigation. The Nationa l Geographic-sponsored work satisfied the need for an internal chronol ogy for the site; the immediate goal now is to obtain additional funding to inventory and an alyze the enormous volume of artifacts and subsistence remains obtained in this project. 11

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12 References Cited Bullen, R. P. and Greene, H. B. (1970) Stratig raphic Tests at Stalli ngs Island, Georgia. Florida Anthropologist 23:8. Claflin, W. H., Jr. (1931) The Stalling's Island Mound, Columbia County, Georgia Cambridge: Peabody Museum of American Archaeology and Ethnol ogy Papers 14(1). Crusoe, D. L. and DePratter, C. B. (1976) A New Look at the Georgia Coastal Shellmound Archaic. Florida Anthropologist 29, 1:1. Elliott, D. T., Ledbetter, R. J. and Gordon, E. A. (1994) Data Recovery at Lovers Lane, Phinizy Swamp and the Old Dike Sites Bobby Jones Expressway Extension Corridor Augusta, Georgia. Atlanta: Occasional Pa pers in Cultural Resource Management 7, Georgia Department of Transportation. Fairbanks, C. H. (1942) The Taxonomic Position of Stallings Island, Georgia. American Antiquity 7:223-231. Sassaman, K. E. (1998b) Distribution, Timing, and Technology of Early Pottery in the Southeastern United States. Revista de Arquelolgia Americana 14:101-133. Williams, S. (1968) Appendix: Radiocarbon Dates from the Georgia Coast, in S. Williams (ed.) The Waring Papers: The Coll ected Works of Antonio J. Waring, Jr., pp. 329-332, Cambridge, Mass.: Papers of th e Peabody Museum of Archaeology and Ethnology, Harvard University. Wood, W. D., Elliott, D. F., Rudolph, T. P., and Blanton, D. B. (1986) Prehistory in the Richard B. Russell Reservoir: The Archaic and Woodland Periods of the Upper Savannah River. Atlanta: Russell Pape rs 1986, Archeological Services National Park Service.