September 22, 1998
New York Times
In Peru, Evidence of an Early Human Maritime Culture
The Discovery of Ancient Camps in Peru and Chile
By JOHN NOBLE WILFORD
About 12,000 years ago, people living in what is now southern Peru camped on the Pacific shore and feasted on fish, seabirds and shellfish. The remains of stone tools, hearths and butchered bird bones found at two Peruvian sites are the earliest known evidence of maritime-based cultures in the New World, scientists reported last week.
The findings, described in the current issue of the journal Science, also provide further proof that people were in America earlier than once thought. Of possibly even more importance, they support an emerging view of how the first Americans lived and how they migrated through the length of North and South America. This rethinking of the peopling of the New World is becoming one of the liveliest areas of research and controversy in American archeology.
In the new view, it appears that the earliest Americans were not all hunters spearing big game like mammoths and bison, as they have long been portrayed in prehistoric studies. The Peruvian discoveries, along with other recent research, show that many of the people who first inhabited the Americas relied on diverse resources for survival: big game and small, plants and fruits, marine life and just about anything at hand.
Dr. Daniel H. Sandweiss of the University of Maine at Orono, who directed research at one of the sites, said in a telephone interview: "This finally makes it abundantly clear that these people had a very diverse subsistence system and were prepared to exploit all different kinds of food sources almost as soon as they arrived in America. We had thought this before, but we can prove it now."
Research by Dr. Anna C. Roosevelt, an archeologist at the Field Museum and the University of Illinois in Chicago, had already found that people living 11,000 years ago in the Amazon basin had opportunistic subsistence economies that seldom included big game. Likewise, the oldest confirmed settlement site in the Americas, at Monte Verde in southern Chile, was occupied 12,500 years ago by people who ate mastodon meat when available but more usually dined on potatoes, mushrooms, grasses, nuts, berries and freshwater shellfish.
"Now there's recognition that early Americans did not live by mammoth alone," said Dr. David J. Meltzer, an archeologist at Southern Methodist University in Dallas, commenting on the Peruvian findings. Until last year, when archeologists finally accepted the antiquity of the Monte Verde site, the earliest confirmed traces of human activity in the Americas had been 11,200-year-old stone spear points discovered in the 1930's near Clovis, N.M. The distinctive points were later found scattered throughout much of the two continents, creating the impression of the first Americans as almost exclusively big-game hunters. This led to the prevailing hypothesis that the New World was first populated in the last ice age when sea levels were low. Hunters walked across a land bridge at the Bering Strait in pursuit of game, then moved south through an ice-free corridor between glaciers in the continental interior and eventually made it by foot all the way to the tip of South America.
Dr. David K. Keefer of the United States Geological Survey in Menlo Park, Calif., a geologist and leader of the team that explored the second Peruvian site, said the new evidence of such early maritime-oriented cultures bolstered the case for an alternative migration theory.
"Our site," he said in a telephone interview, "is about the best kind of evidence you're going to find for the idea of coastal migration -- not conclusively probably, but very strong evidence."
Dr. Knut Fladmark, an archeologist at Simon Fraser University in Vancouver, British Columbia, proposed the coastal migration hypothesis in the 1970's, but the idea gained few adherents until recently. Geologic and paleoenvironmental studies have begun showing that there probably was not a clear passage between the glaciers early enough to enable people to migrate through the North American interior in time to reach places as far south as Peru, Brazil and Chile when new archeological evidence establishes that they were there.
New estimates, Fladmark said last week, indicate that the corridor between the glaciers, on the eastern flank of the Rocky Mountains, did not open until 11,500 years ago. If the newcomers to America could not move south through the interior, they might have migrated along the western coast, on foot along the shore and by skin-covered boats for stretches.
Sandweiss is reserving judgment as to whether the Peruvian sites support the coastal-migration hypothesis. At the site he studied, the people appeared to have occupied it seasonally and spent the rest of the year in the nearby highlands, possibly engaged mostly in hunting.
"The coastal migration is possible, but neither site provides clear evidence for it at this time," Sandweiss said. "We need a good number more sites up and down the coast to establish anything about migrations."
An advocate of the coastal-migration hypothesis, Dr. Carole A.S. Mandryk of Harvard University, said the Peruvian findings "make me really happy" because they show a culture oriented to the sea and its resources that was living as far south as Peru early enough that their ancestors presumably could not have found a way through the interior glaciers of the ice age. Instead, she said, they would probably have taken the coastal route.
Finding evidence of early coastal settlements and migrations was once thought to be hopeless. At the end of the ice age, melting glaciers raised sea levels and inundated what had been the ancient shorelines. But off Peru, the sea floor drops off so steeply that when the sea levels rose, not much land was submerged. Buried remains of settlements close to the ice-age coast might still be recoverable
Both discovery sites are in the arid south of Peru, near Arequipa. The site Keefer's group excavated, called Quebrada Tacahuay, was about a half-mile from the present shore. As a geologist, Keefer was originally looking for buried evidence of the effects of ancient El Niños on early cultures. Layers of sediments revealed deposits of mud and rock from floods brought about by El Niño, a Pacific Ocean warm-water current that every few years generates storms and heavy rain along the western coasts of the Americas and droughts in Australia and Asia.
Deep among the flood deposits, the geologists and archeologists found the charcoal and stones of a cooking hearth, radiocarbon dated at 10,700 years, or about 12,700 calendar years old. Further exploration turned up an abundance of seabird bones, particularly cormorants and boobies. Butcher marks suggest that the people were removing the meaty breast parts. The second most abundant remains were anchovy bones. Only a few bones of terrestrial animals were found.
"The remains of such small, schooling fish at the site suggest the use of specialized fish-netting technology," the scientists reported in the Science article.
The second site, called Quebrada Jaguay and worked by Sandweiss's group, was a few miles inland by the bed of seasonal stream flowing out of the highlands to the coastal desert. People occupied the site for a time 13,000 to 11,000 years ago, gathering clams and small fish of the drum family. Archeologists found some stone tools, petrified wood and small pieces of obsidian as cutting tools.
In their Science report, Sandweiss and his colleagues said the bones and stones at Quebrada Jaguay suggest that the people there were foragers who spend part of their time in the highlands and part on the coast exploiting marine resources. While at the shore, they relied almost exclusively on the sea for food.
"This conclusion supports other recent studies showing early diversification of subsistence beyond an economy based on the hunting of large game," the scientists wrote.
Early Maritime Economy and El Niño Events at Quebrada Tacahuay, Peru
David K. Keefer, * Susan D. deFrance, Michael E. Moseley, James B. Richardson III, Dennis R. Satterlee, Amy Day-Lewis
The archaeological site of Quebrada Tacahuay, Peru, dates to 12,700 to 12,500 calibrated years before the present (10,770 to 10,530 carbon-14 years before the present). It contains some of the oldest evidence of maritime-based economic activity in the New World. Recovered materials include a hearth, lithic cutting tools and flakes, and abundant processed marine fauna, primarily seabirds and fish. Sediments below and above the occupation layer were probably generated by El Niño events, indicating that El Niño was active during the Pleistocene as well as during the early and middle Holocene.
D. K. Keefer, U.S. Geological Survey MS 977, 345 Middlefield Road, Menlo Park, CA 94025, USA. S. D. deFrance, Corpus Christi Museum of Science and History, 1900 North Chaparral Street, Corpus Christi, TX 78401, USA. M. E. Moseley, Department of Anthropology, University of Florida, Gainesville, FL 32611, USA. J. B. Richardson III, Division of Anthropology, Carnegie Museum of Natural History, and Department of Anthropology, University of Pittsburgh, 5800 Baum Boulevard, Pittsburgh, PA 15206, USA. D. R. Satterlee, Department of Geosciences, Northeast Louisiana University, Monroe, LA 71209, USA. A. Day-Lewis, Department of Geophysics, Stanford University, Stanford, CA 94305, USA.
To whom correspondence should be addressed. E-mail: firstname.lastname@example.org
The lowland coastal plain of Peru was evidently first settled during the Terminal Pleistocene period (1-5), when much of the rest of the New World was probably also first occupied (6). Many of the earliest lowland Peruvian sites are in the north and are more than 24 km from the paleoshoreline of the Pacific Ocean (1, 2), thus making them part of an interior-oriented settlement pattern (1). However, at least some early migration into and through the Americas may have taken place along coastal routes by people with maritime-based economies (7). In addition, specialized maritime-resource procurement was important in the later development of complex state-level societies along the Peruvian coast (8). Knowledge of the degree to which the earliest coastal plain inhabitants exploited maritime resources may contribute to a better understanding of both processes. Previous work identified maritime components in the remains from some early sites in the north (2, 3) and from the Ring Site, the oldest previously described site along the far south coast (5). Evidence is now available concerning economic activity at two additional Terminal Pleistocene sites along the far south coast: Quebrada Jaguay, described elsewhere in this issue by Sandweiss et al. (9), and Quebrada Tacahuay, which we describe here (Fig. 1).
Fig. 1. Site plan and location. Contour interval 2.5 m. Filled squares and circles show locations of samples. Squares are samples containing lithic tools or flakes. Samples 39 and 44 contain both lithic materials and bones. Open squares show locations of lithic artifacts found on the surface. RS is the Ring Site and QJ is Quebrada Jaguay.
Profiles at Quebrada Tacahuay also expose 19 debris-flow and flood deposits. In this region today such deposits are associated with El Niño events, which typically cause widespread torrential rainfall, flooding, and disruption of fisheries (10), such as occurred in early 1998. Identifying prehistoric El Niño events is important to evaluating the El Niño mechanism. Some previous work indicates that El Niño events have occurred throughout the Holocene and probably much longer (11), but one recent study (12) concluded that such events did not occur from about 5000 to 8000 14C years before the present (yr B.P.) [about 5700 to 8900 calibrated (cal.) yr B.P.] or earlier.
The site we describe at Quebrada Tacahuay is 0.3 to 0.4 km inland at 17.8°S (Fig. 1). It is on an alluvial fan, about 2 km southeast of a prominent and rocky coastal headland. The current climate is hyperarid; mean annual rainfall is about 5 mm. Sediments containing archaeological materials are exposed along five near-vertical artificial cuts, as high as 7 m, made for a road and a water pipeline (Fig. 1). The cut faces are currently 47 to 56 m above sea level. When the site was occupied sea level was 60 to 70 m lower than at present (13), and the site would probably have been 0.7 to 0.9 km farther inland then.
The northeastern-most cut (profile 1, Fig. 1) exposes a hearth, 50 cm by 8 cm in cross section, composed of a cohesive mixture of ash, sand, and charcoal. Two 14C age determinations on this charcoal have calibrated means of 12,670 and 12,730 cal. yr B.P. (10,750 ± 80 and 10,770 ± 150 14C yr B.P.; Table 1 and Fig. 2). The hearth is in a 10- to 50-cm-thick stratum composed of fine aeolian sand locally interbedded with lenses of water-laid, desiccation-cracked silt (unit 8, Fig. 2). Because the sand is loose and susceptible to wind erosion, this stratum commonly forms cave-like recesses along cut faces, and some coarse materials are scattered on the deflated sand surface.
Table 1. Radiocarbon dates from Quebrada Tacahuay, Peru. All samples were analyzed by Beta Analytic, Miami, Florida, and all dates were corrected for 13C/12C ratios. Dates younger than 10,000 14C yr B.P. were dendrocalibrated by Beta Analytic. Older dates were calibrated with the University of Washington, Quaternary Isotope Lab Radiocarbon Calibration Program, Calib 3.0.3 Method A (17). The age range given in the last column has a 95% probability.
Profile unit Sample number/ type* Material/context Uncalibrated age mean ± (14C yr B.P.) Calibrated intercept/ mean (cal. yr B.P.) Calibrated ±2 age range (cal. yr B.P.)
1-1 108536A Bulk sediment/debris flow 4,550 ± 60 5,290 5,540-4,995 4-c3 109354C Charcoal/midden 7,990 ± 80 8,940 9,005-8,550 2-2 108861A Root/debris flow 7,920 ± 80 8,655 8,975-8,485 2-3 110330A Root/debris flow 8,430 ± 60 9,435 9,490-9,350 1-4 108858A Charcoal/sheetflood 9,550 ± 90 10,560 10,960-10,355 1-4 108859A Terrestrial gastropod shell 9,630 ± 60 10,895 10,970-10,520 3A-8 108860C Charcoal pieces interspersed with lithic flakes 10,530 ± 140 12,490 12,790-12,070 1-8 108692A Charcoal/hearth 10,750 ± 80 12,670 12,860-12,460 1-8 95869C Charcoal/hearth 10,770 ± 150 12,730 13,030-12,390
* A indicates accelerator mass spectrometry analysis and C indicates conventional radiometric analysis.
Fig. 2. Composite stratigraphic column compiled from profiles 1, 2, 3A, and 4, showing relations and thicknesses of units 1 to 8, 4c1 to 4c3, and the uppermost part of unit 9. Unit 8 is the occupation layer, containing the hearth, lithic artifacts, and faunal remains. Units 1 to 5 and 7 to 9 are present in all profiles. Unit 6 is present in profiles 1, 2, and 4. Units 4c1 to 4c3 are present only in a small paleochannel that locally truncates units 2 through 8 in the central part of profile 4. Radiocarbon dates are calibrated means or intercepts (in calibrated years before the present), from Table 1.
Because of typical overburden depths of several meters above unit 8, we elected to sample the occupation layer by excavating horizontal sections 20 cm to 1 m long from exposed cut faces. In addition to the hearth, we selected areas for sampling (Fig. 1) on the basis of locations of exposed bones and two lithic artifacts. We collected bulk samples of sediment and hearth material using trowels and brushes. All excavated material was sifted dry through a 2.00-mm fiberglass mesh. We removed 2.0 liters of material from the hearth. Volumes of other bulk samples ranged from 0.3 to 0.9 liter. Pieces of charcoal, found interspersed with lithic flakes in sample 44 (Fig. 1), were dated to 12,490 cal. yr B.P. (10,530 ± 140 14C yr B.P.; Table 1 and Fig. 2).
All analyzed faunal remains were from excavated material found in place in the hearth or in unit 8 sediment (Fig. 1). Among these remains, seabirds are the most abundant (number of elements, n = 3484; minimum number of individuals, MNI = 16). The guanay cormorant (Phalacrocorax bougainvillii) is the most abundant species (n = 181, MNI = 7). Also present are the Neotropical cormorant (Phalacrocorax brasilianus; n = 6, MNI = 2), undetermined species of booby (Sula spp.; n = 79, MNI = 5) and cormorant (Phalacrocorax spp.; n = 64, MNI = 1), and one immature pelican (Pelecanus sp.; n = 1). Although the remains are well preserved, most elements are unidentified bird shaft fragments (n = 3153).
Marine fish (Osteichthyes) are the second most abundant remains (n = 280; MNI = 13). Species present include anchoveta (Engraulis ringens), anchovy (Anchoa spp.), and an unidentified bony fish (Osteichthyes uid). The anchovy remains are the earliest known from an archaeological context in the New World, and remains of such small, schooling fish at the site suggest the use of specialized fish-netting technology. Fragments of three marine mollusks were found in the hearth: a Veneroid clam, a choro mussel (Choromytilus chorus), and an unidentified mollusk (14). Of the 3775 bones and shell fragments recovered from the site, only eight (0.2%) are terrestrial: four shell fragments from unidentified terrestrial gastropods, three rodent bones, and one unidentified tetrapod bone.
Butchering is evident from cut marks on 18 seabird bones, all from axial and forelimb parts of the skeleton (15), where most cut locations suggest that the meaty breast parts of the birds were removed. Fifteen butchered specimens were found with lithic debitage in profile 3A, and three were found in the hearth. Twenty percent of the seabird bones (n = 692) were burned, and these burned remains were also concentrated in the hearth and near the lithic artifacts. A few (n = 8) anchovy (Engraulidae) and unidentified bony fish (Osteichthyes) specimens (n = 7) were burned, and 22 anchovy vertebrae are slightly discolored, suggesting low-temperature alteration.
Lithic artifacts comprise one tool and 17 smaller flakes recovered from excavated unit 8 sediment (Fig. 1) and two tools (31a and 31b, Fig. 1) found on the surface in contexts indicating they were derived from unit 8 (16). All artifacts have features consistent with use as cutting tools, and all are composed of chalcedony. All are unifacial, but the largest also has a bifacial cutting edge (Fig. 3). Eight of the smaller flakes are evidently debitage from tool manufacture, whereas nine are probably use or resharpening flakes. Artifact materials and other characteristics are similar to those in the assemblage recovered from the approximately contemporary Ring Site 20 km to the north (5); these similarities suggest that there was some association between populations at the two sites.
Fig. 3. Bifacially edged artifact (31b in Fig. 1).
The occupation at Quebrada Tacahuay may have been abandoned when the site was inundated by a debris flow, because partly articulated seabird bones from the occupation layer were impressed into the base of the overlying debris-flow deposit (unit 7, Fig. 2). Other sediments covering the occupation layer in at least three of the profiles include four debris-flow deposits (units 1, 2, 3, and 6, Fig. 2), a sheetflood deposit composed of sand and gravel (unit 4, Fig. 2), and a layer of aeolian sand (unit 5, Fig. 2). Additionally, profile 4 exposes a small paleochannel, cut into units 2 through 8 and capped by unit 1. This paleochannel contains an additional aeolian sand layer (unit 4c3, Fig. 2) overlain by two thin and fine-grained, channelized debris-flow deposits (units 4c1 and 4c2, Fig. 2). Embedded in the aeolian deposit (unit 4c3) is a dense shell midden from a younger occupation (Table 1 and Fig. 2). A flood deposit consisting of coarse, bouldery sands and gravels as much as 3.5 m thick (unit 9, Fig. 2) underlies unit 8 throughout the site. Older units, exposed in profile 3 and the southeastern part of profile 3A, consist of eight debris-flow deposits, three layers of aeolian sand, and two flood deposits.
All of the debris-flow deposits are massive and contain coarse clasts distributed in cohesive sand-silt-clay matrices. All except unit 1 are red, reddish brown, or reddish yellow in color. Unit 1 is dark brown to gray, probably due to incorporation of significant organic material. Several debris-flow deposits contain desiccation cracks filled with aeolian sand or are capped by thin aeolian lenses or layers.
All sediments except the aeolian sands and the unit 8 silts are of types typically produced by intense precipitation, high flood discharge, or both. Characteristics that also indicate deposition under arid conditions include (i) the desiccation cracks in many deposits, (ii) the aeolian sands, (iii) the absence of in situ soil development in any unit, (iv) the lack of significant organic material in any unit below unit 1, and (v) the lack of evidence of vegetation growth except locally within units 2 and 3. Because intense precipitation along the arid Peruvian coast is typically associated with El Niño events today, we infer that such events also produced the debris-flow and flood deposits at Quebrada Tacahuay.
Radiocarbon dating of units 1, 2, 3, 4, 4c3, and 8 (Table 1 and Fig. 2) divide the sedimentary history of the site after deposition of unit 8 into three periods. First, between about 12,500 and 8900 to 8700 cal. yr B.P., four extensive debris flows (units 2, 3, 6, and 7) and an extensive sheetflood (unit 4) covered the site--an average of one sedimentation event every 700 to 800 years. In contrast, between about 8900 to 8700 and about 5300 cal. yr B.P., the only flood or debris-flow sediments deposited were two thin and fine-grained debris-flow units confined to a small channel and exposed in only one profile (units 4c1 and 4c2, Fig. 2). Flood and debris-flow activity thus diminished significantly in both severity and frequency during this period, which corresponds to the ~8900 to 5700 cal. yr B.P. (8000 to 5000 14C yr B.P.) hiatus in El Niño activity deduced from shell-midden data farther north (12). Finally, at ~5300 cal. yr B.P., another extensive debris-flow deposit (unit 1) covered the site at Quebrada Tacahuay before sediment supply was cut off by incision of the present main channel (Fig. 1). The debris-flow and flood deposits underlying unit 8 have not been dated but are older than the ~12,700 to 12,500 cal. yr B.P. age of that unit. The similarities between them and the younger sediments suggest that conditions producing El Niño events were also present there in the Pleistocene.
The Quebrada Tacahuay site was almost certainly used largely or entirely for obtaining maritime resources as indicated by the overwhelming proportion of maritime elements (99.8%) in the faunal remains. Indications that most or all of these remains were associated with anthropogenic activity include evidence of butchering, the large numbers of burned bones, the presence of marine mollusk fragments, and the spatial association of the remains with the hearth and lithic artifacts. The primary activity at the site evidently was processing seabirds, and secondary activities included processing fish and shellfish. We therefore infer that people with a maritime-based economy were present there about 12,700 to 12,500 years ago, during the period when the Andean coast was first settled. After that time, catastrophic floods and debris flows may have affected the occupation history of the site. A debris flow inundated the site, possibly when it was still in use, and the locality was not reoccupied until ~3500 years later, when flood and debris-flow activity had substantially diminished.
REFERENCES AND NOTES
- M. Aldenderfer, Quat. Int., in press.
- C. Chauchat, in Peruvian Prehistory, R. W. Keatinge, Ed. (Cambridge Univ. Press, Cambridge, 1988), pp. 41-66.
- J. B. Richardson III, in Early Man in America, A. L. Bryan, Ed. (Archaeological Researches International, Edmonton, Alberta, 1978), pp. 274-289; Rev. Arqueología Am. 6, 71 (1992).
- P. P. Ossa, in Early Man in America, A. L. Bryan, Ed. (Archaeological Researches International, Edmonton, Alberta, 1978), pp. 290-295; C. Chauchat, Préhistoire de la Côte Nord du Pérou (Cahiers du Quaternaire, no. 18, CNRS, Paris, 1992).
- D. H. Sandweiss, J. B. Richardson III, E. J. Reitz, J. T. Hsu, R. A. Feldman, in Ecology, Settlement, and History in the Osmore Drainage, Peru, D. S. Rice, C. Stanish, P. R. Scarr, Eds. (Br. Archaeol. Rep. Int. Ser. 545i, 1989), pp. 35-84.
- A. C. Roosevelt, et al., Science 272, 373 (1996) [Abstract]; R. E. Taylor, C. V. Haynes Jr., M. Stuiver, Antiquity 70, 515 (1996).
- For recent discussions, see papers presented at Society for American Archaeology's 63rd Annual Meeting Symposium on Terminal Pleistocene/Early Holocene Maritime Adaptations Along the Pacific Coast of the Americas, 27 March 1998, Seattle, WA.
- M. E. Moseley, The Maritime Foundations of Andean Civilization (Cummings, Menlo Park, CA, 1975); Andean Past 3, 5 (1992).
- D. H. Sandweiss, et al., Science 281, 1830 (1998) .
- See, for example, C. N. Caviedes, Geogr. Rev. 74, 267 (1984).
- L. E. Wells, J. Geophys. Res. 92, 14463 (1987); thesis, Stanford University, Stanford, CA (1988); Geology 18, 1134 (1990); L. Ortlieb, T. J. DeVries, A. Díaz, Bol. Soc. Geol. Perú 81, 127 (1990); A. Díaz and L. Ortlieb, Bull. Inst. Fr. Et. Andines 22, 159 (1993); L. Ortlieb and J. Macharé, Global Planet. Change 7, 181 (1993); L. Ortlieb, A. Díaz, N. Guzman, Quat. Sci. Rev. 15, 857 (1996); T. J. DeVries, L. Ortlieb, A. Díaz, L. E. Wells, C. Hillaire-Marcel, Science 276, 965 (1997) [Full Text]; L. E. Wells and J. S. Noller, ibid., p. 966.
- D. H. Sandweiss, J. B. Richardson III, E. J. Reitz, H. B. Rollins, K. A. Maasch, Science 273, 1531 (1996) [Abstract]; ibid. 276, 966 (1997).
- E. Bard, et al., Nature 382, 241 (1996) .
- The marine mollusk fragments are almost certainly of anthropogenic origin, as evidenced by their terrestrial location and context. Fish remains may be transported in the digestive systems of seabirds [ D. G. Ainley, D. W. Anderson, P. R. Kelley, Condor 83, 120 (1981) ; D. C. Duffy and L. J. B. Laurenson, ibid. 85, 305 (1983) ], but the burned anchovy remains in the hearth and the lack of any evidence of digestive changes from stomach acids indicate that the fish remains are also of anthropogenic origin.
- The following skeletal elements contain butchering evidence: Sula spp. (booby)--one furcula, two coracoids, one scapula, one ulna; Pelecanus sp. (pelican)-one digit; Phalacrocorax bougainvillii (guanay cormorant)--one scapula, three humeri; Phalacrocorax spp. (cormorant)--one furcula, one coracoid, one radius, one ulna; Aves unidentified--one rib, one radius, two shaft fragments.
- One artifact (31b, Fig. 1) was on the deflated sand surface of unit 8, under an overhang. The other (31a, Fig. 1) was on the surface immediately below the contact between units 8 and 9, partly covered by a thin layer of slope wash.
- M. Stuiver and P. J. Reimer, Radiocarbon 35, 215 (1993).
- We thank J. Alley, M. E. Moseley, and P. R. Williams for assistance in the field; the Asociación Contisuyo del Perú for logistical and financial support; the Florida Museum of Natural History for access to comparative skeletal collections; and K. R. Lajoie, D. H. Sandweiss, D. W. Steadman, and L. E. Wells for comments.
4 June 1998; accepted 31 July 1998
Volume 281, Number 5384 Issue of 18 Sep 1998, pp. 1833 - 1835
©1998 by The American Association for the Advancement of Science.
Copyright © 1998 by the American Association for the Advancement of Science.