Pre-Clovis projectile points at the Debra L. Friedkin site, Texas—Implications for the Late Pleistocene peopling of the Americas

Waters, Michael R.; Keene, Joshua L.; Forman, Steven L.; Prewitt, Elton R.; Carlson, David L.; Wiederhold, James E.

doi:10.1126/sciadv.aat4505

Cited by 115Pleistocene-Era Hominins and ArchaeologyArchaeology and ancient environmental studiesGeology and Paleoclimatology Research

The DOI matches its Crossref record; 39 of the 39 references it cites were found in a registry or an index; 2 of the 82 sources its claims cite were checked for support.

Pre-Clovis projectile points at the Debra L. Friedkin site, Texas—Implications for the Late Pleistocene peopling of the Americas

Open access

Waters, Michael R., Keene, Joshua L., Forman, Steven L., Prewitt, Elton R., Carlson, David L., Wiederhold, James E.·2018·Science Advances

DOI 10.1126/sciadv.aat4505PMC PMC6200361

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Abstract

Stemmed projectile points are ~13,500 to ~15,500 years old and lie stratigraphically below ~13,000-year-old Clovis artifacts., Lanceolate projectile points of the Clovis complex and stemmed projectile points of the Western Stemmed Tradition first appeared in North America by ~13 thousand years (ka) ago. The origin, age, and chronological superposition of these stemmed and lanceolate traditions are unclear. At the Debra L. Friedkin site, Texas, below Folsom and Clovis horizons, we find stemmed projectile points dating from ~13.5 to ~15.5 ka ago, with a triangular lanceolate point form appearing ~14 ka ago. The sequential relationship of stemmed projectile points followed by lanceolate forms suggests that lanceolate points are derived from stemmed forms or that they originated from two separate migrations into the Americas.

AI snapshot

Written from the paper’s full text.

TL;DR

At the Debra L. Friedkin site, Texas, 12 complete and fragmentary stemmed and triangular lanceolate projectile points from the Buttermilk Creek Complex are dated by 19 OSL ages to ~13.5–15.5 ka, stratigraphically below Folsom-Clovis. The authors argue these pre-Clovis points support an early stemmed-point tradition and present two models for the Late Pleistocene peopling of the Americas, including possible in situ development of Clovis or a separate later migration.

Key findings

The Buttermilk Creek Complex horizon yielded ~100,000 artifacts, including 328 tools and 12 complete and fragmentary projectile points, dated to ~13.5–15.5 ka by 19 OSL ages and lying 15–20 cm below the Folsom-Clovis zone.
The projectile point assemblage includes lanceolate stemmed forms and a triangular lanceolate form; lanceolate stemmed points are confined exclusively to the Buttermilk Creek Complex horizon and are absent from post–13-thousand-year-old sediments.
Across the Late Prehistoric to Clovis horizons, 130 time-diagnostic artifacts form four mutually exclusive chronological zones, with no in situ diagnostics from one zone found in overlying or underlying zones; the authors use this to argue against downward artifact movement and for stratigraphic integrity.
OSL ages overlap known ages for later diagnostics: the Clovis point base is bracketed by 12,500 ± 480 and 12,950 ± 480 yr B.P.; the Folsom-Clovis zone ranges from 11,980 ± 490 to 13,590 ± 720 yr B.P.; Late Paleoindian ages range from 9,590 ± 370 to 11,980 ± 555 yr B.P.; Middle/Early Archaic ages range from 7,295 ± 315 to 9,000 ± 375 yr B.P.

Methods

Excavated 104 m² of Block A at the Debra L. Friedkin site (41BL1239) in 2006–2009 and 2015–2016 using 1 m by 1 m units, generally 5- and 2.5-cm levels, with artifacts mapped in Paleoindian levels and sediments screened through 6.35-mm and 3.175-mm mesh.
OSL dating targeted the 4- to 11-μm quartz fraction from clay-rich distal overbank sediments; 70 OSL ages were obtained from Late Pleistocene and Early Holocene sediments, including 38 previously published and 32 new ages, using single aliquot regeneration protocols.
Bayesian models in OxCal using a Poisson deposition model were created for four OSL columns to identify outliers and compute posterior age estimates; artifact analysis included time-diagnostic projectile points, use-wear, and biface technology comparisons.

Limitations

The paper states that radiocarbon dating was not used because no carbon samples would yield reliable ages: in situ charcoal is not preserved, all bones are leached of collagen, and bulk sediment organics were avoided as usually inaccurate.
The paper states that some projectile point types are poorly dated, that two OSL ages appear too young for Angostura, and that older point types can be found in younger contexts because prehistoric people sometimes picked up older points; it also notes a few Late Prehistoric/Archaic points are out of chronological order due to repeated use of cooking features.
Evident from the text: OSL ages carry large uncertainties (e.g., ±360 to ±880 years), and several point fragments occur 2.4 to 5.3 m from the nearest OSL column, so their ages rely on stratigraphic correlation; the paper also states that more excavations of buried and datable Late Pleistocene sites are needed to test the proposed models.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1126/sciadv.aat4505

Cites

39 of 39 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

2 of 82 cited sources checked · 1 supported · 0 flagged · accuracy not yet measured

Findingown data
Seven of the 11 projectile points and point fragments occur in close proximity to specific OSL ages.
“Seven of the 11 projectile points and point fragments occur in close proximity to specific OSL ages.”
Quote in the paperSubstantial claim
Findingown data
A 10-cm-thick zone with Folsom and Clovis artifacts occurs below the Late Paleoindian horizon.
“A 10-cm-thick zone with Folsom and Clovis artifacts occurs below the Late Paleoindian horizon (Figs. 2 and 3).”
Quote in the paperNot a substantial claim
Findingown data
The Buttermilk Creek Complex artifacts are dated to ~13.5 and ~15.5 ka ago by 19 OSL ages.
“These artifacts are dated to ~13.5 and ~15.5 ka ago by 19 OSL ages (table S2).”
Quote in the paperSubstantial claim
Findingown data
Seven ages from the Folsom-Clovis zone range from 11,980 ± 490 yr B.P. to 13,590 ± 720 yr B.P.
“Seven ages from the Folsom-Clovis zone range from 11,980 ± 490 yr B.P. (BG4208) to 13,590 ± 720 yr B.P. (UIC2059; Figs. 2 and 3 and table S2).”
Quote in the paperNot a substantial claim
Findingown data
Lanceolate stemmed points include one complete specimen, one base fragment, four medial fragments, and five tips.
“Lanceolate stemmed points include one complete specimen, one base fragment, four medial fragments, and five tips (Fig. 5, fig. S6, and table S3).”
Quote in the paperNot a substantial claim

Findingnone given
Within a zone, most projectile points are in correct chronological order.
“Within a zone, most projectile points are in correct chronological order.”
Quote in the paperSubstantial claim
Findingown data
Seventy OSL ages were obtained from the Late Pleistocene and Early Holocene sediments of Block A.
“Seventy OSL ages were obtained from the Late Pleistocene and Early Holocene sediments of Block A (Figs. 1 to 3 and figs. S1 to S3).”
Quote in the paperSubstantial claim
Findingown data
A single OSL age of 1000 ± 70 yr B.P. was obtained from the Late Prehistoric and Late Archaic horizon associated with the Ensor and Ellis points at the Friedkin site.
“A single OSL age of 1000 ± 70 yr B.P. (UIC2352; Figs. 2 and 3 and table S2) was obtained from the Late Prehistoric and Late Archaic horizon associated with the Ensor and Ellis points at the Friedkin site.”
Quote in the paperNot a substantial claim
Findingown data
Six OSL ages from the Middle Archaic and Early Archaic horizon at the Friedkin site range from 7295 ± 315 yr B.P. to 9000 ± 375 yr B.P.
“Six OSL ages from the Middle Archaic and Early Archaic horizon at the Friedkin site range from 7295 ± 315 yr B.P. (UIC2360) to 9000 ± 375 yr B.P. (UIC2061; Figs. 2 and 3 and table S2).”
Quote in the paperNot a substantial claim
Findingown data
End thinning and base beveling in preparation for end thinning found on Clovis preforms are absent in the pre-13-thousand-year-old biface assemblage.
“End thinning and base beveling in preparation for end thinning found on Clovis preforms are absent in the pre–13-thousand-year-old biface assemblage.”
Quote in the paperSubstantial claim
Findingcitation
The authors report a robust lithic projectile point assemblage from layers dated between ~13.5 and 15.5 ka ago at the Debra L. Friedkin site, Texas.
“Here, we report a robust lithic projectile point assemblage from the layers dated between ~13.5 and 15.5 ka ago at the Debra L. Friedkin site, Texas (11), which has implications for the origin of both the ~13-thousand-year-old lanceolate and stemmed point traditions of North America.”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
Findingown data
Lanceolate stemmed points at the Friedkin site are confined to the clays dating between ~13.5 and ~15.5 ka ago.
“Lanceolate stemmed points at the Friedkin site are confined to the clays dating between ~13.5 and ~15.5 ka ago (Figs. 2 and 3 and table S2).”
Quote in the paperSubstantial claim
Findingown data
Bayesian analyses of all OSL ages from four sediment columns yielded modeled ages with reduced SDs.
“Bayesian analyses of all OSL ages from four sediment columns yielded modeled ages with reduced SDs (fig. S1 and table S2).”
Quote in the paperSubstantial claim
Findingcitation
The time-diagnostic artifacts group into four mutually exclusive zones that correspond to the prehistoric cultural periods of central Texas.
“These artifacts group into four mutually exclusive zones that correspond to the prehistoric cultural periods of central Texas (18, 19).”
Quote in the paperSubstantial claim0 of 2 sources checked
- cites [18] M. B. Collins, Archeology in Central Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 101–126.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [19] Lohse J., Black S. L., Cholak L. M., Toward an improved Archaic radiocarbon chronology for Central Texas. Bull. Texas Archeol. Soc. 85, 259– 287 (2014).
Findingown data
Fourteen OSL ages, ranging from 9590 ± 370 yr B.P. to 11,980 ± 555 yr B.P., are from the Late Paleoindian horizon at the Friedkin site.
“Fourteen OSL ages, ranging from 9590 ± 370 yr B.P. (UIC2363) to 11,980 ± 555 yr B.P. (UIC2048; Figs. 2 and 3 and table S2), are from the Late Paleoindian horizon at the Friedkin site.”
Quote in the paperNot a substantial claim
Findingnone given
Four points (one Pedernales, one Bonham, one Darl, and one Castroville) are out of chronological order within the Late Prehistoric and Late Archaic zone.
“Four points (one Pedernales, one Bonham, one Darl, and one Castroville) are out of chronological order within the Late Prehistoric and Late Archaic zone.”
Quote in the paperNot a substantial claim
Findingown data
The OSL dates from the Late Paleoindian horizon encompass the known ages for the various Late Paleoindian projectile point types.
“These OSL dates encompass the known ages for the various Late Paleoindian projectile point types.”
Quote in the paperNot a substantial claim
Findingown data
In situ diagnostics of one zone are not found in overlying or underlying zones.
“In situ diagnostics of one zone are not found in overlying or underlying zones.”
Quote in the paperSubstantial claim
Findingown data
About 100,000 artifacts, including 328 tools and 12 complete and fragmentary projectile points of the Buttermilk Creek Complex, were excavated from the floodplain clays, 15 to 20 cm below the Folsom-Clovis zone.
“About 100,000 artifacts, including 328 tools and 12 complete and fragmentary projectile points of the Buttermilk Creek Complex, were excavated from the floodplain clays, 15 to 20 cm below the Folsom-Clovis zone (Figs. 2 to 5).”
Quote in the paperSubstantial claim
Findingown data
All specimens show microscopic use-wear consistent with hafting and use as projectile points.
“All specimens show microscopic use-wear consistent with hafting and use as projectile points (fig. S8).”
Quote in the paperSubstantial claim
Findingown data
The Buttermilk Creek Complex projectile point assemblage includes lanceolate stemmed and triangular lanceolate forms.
“Here, we describe the Buttermilk Creek Complex projectile point assemblage that includes lanceolate stemmed and triangular lanceolate forms (Fig. 5 and fig. S6).”
Quote in the paperNot a substantial claim
Findingown data
The bifaces show no evidence of end thinning or preparation of a beveled base for later fluting.
“The bifaces show no evidence of end thinning or preparation of a beveled base for later fluting.”
Quote in the paperSubstantial claim
Findingown data
A broken triangular lanceolate projectile point (AM9811-1) occurs in the uppermost portion of the clays ranging in age from ~13.5 to ~14 ka ago, below the Clovis horizon.
“A broken triangular lanceolate projectile point (AM9811-1) occurs in the uppermost portion of the clays ranging in age from ~13.5 to ~14 ka ago, below the Clovis horizon (Fig. 5A, fig. S6, and table S3).”
Quote in the paperSubstantial claim
Findingown data
The 2007 column of OSL ages shows agreement indices of 115.4/116.7 with a single outlier (UIC2050).
“The 2007 column of OSL ages shows agreement indices of 115.4/116.7 (model and overall agreement) with a single outlier (UIC2050).”
Quote in the paperNot a substantial claim
Findingreasoning
Intense use of the Friedkin site over time combined with slow deposition has resulted in no clear indication of multimodal distribution of artifacts when all tools and debitage are considered.
“Intense use of the Friedkin site over time combined with slow deposition has resulted in no clear indication of multimodal distribution of artifacts when all tools and debitage are considered (Fig. 4A).”
Quote in the paperSubstantial claim
Findingown data
At the Debra L. Friedkin site, total lithic tools and debitage generally increase through time from the Late Pleistocene through the Holocene.
“At the Friedkin site, there is a general increase through time in total lithic tools and debitage”
Quote in the paperNot a substantial claim
Findingown data
A large increase in tools at 90.50 to 90.45 m AD correlates with the top of the Folsom and Clovis horizon.
“A large increase in tools at 90.50 to 90.45 m AD correlates with the top of the Folsom and Clovis horizon”
Quote in the paperNot a substantial claim
Findingown data
An assemblage of stemmed projectile points associated with other artifacts was found below a Folsom and Clovis artifact-bearing layer at the Debra L. Friedkin site along Buttermilk Creek, Texas, dated to ~13.5 to ~15.5 ka ago.
“Here, we reported an assemblage of stemmed projectile points associated with other artifacts, below a Folsom and Clovis artifact–bearing layer at the Debra L. Friedkin site along Buttermilk Creek, Texas, dated to ~13.5 to ~15.5 ka ago.”
Quote in the paperSubstantial claim
Findingown data
When only the quantities of formal and informal tools with depth are plotted, multiple modes of artifact concentrations appear.
“When only the quantities of formal and informal tools with depth are plotted (Fig. 4, B and C), multiple modes of artifact concentrations appear”
Quote in the paperSubstantial claim
Findingnone given
A new point form, a triangular lanceolate point, appears at the Friedkin site by ~14 ka ago.
“A new point form, a triangular lanceolate point, appears at the Friedkin site by ~14 ka ago.”
Quote in the paperSubstantial claim
Findingcitation
A previous study of artifact size classes with depth at the Friedkin site showed no change in relative size class from the surface down to 90.225 m AD for artifacts larger than 0.625 cm in diameter.
“Furthermore, a previous study of artifact size classes with depth at the Friedkin site (11, 16) showed no change in relative size class from the surface down to 90.225 m AD for artifacts larger than 0.625 cm in diameter.”
Quote in the paperSubstantial claim0 of 2 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
- cites [16] Driese S. G., Nordt L. C., Waters M. R., Keene J. L., Analysis of site formation history and potential disturbance of stratigraphic context in Vertisols at the Debra L. Friedkin archaeological site in central Texas, USA. Geoarchaeology 28, 221– 248 (2013). source
Findingown data
When the number of formal and informal tools is plotted with depth in the 2015-2016 excavation area, the same peaks in the number of tools are still present but offset ~10 cm due to slope.
“When the number of formal and informal tools is plotted with depth, the same peaks in the number of tools are still present but offset ~10 cm due to slope (Fig. 4, D and E).”
Quote in the paperSubstantial claim
Premisecitation
In South America, humans occupied Monte Verde, Chile, by ~14.2 ka ago.
“In South America, humans occupied Monte Verde, Chile, by ~14.2 ka ago (3)”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [3] Dillehay T. D., Ramírez C., Pino M., Collins M. B., Rossen J., Pino-Navarro J. D., Monte Verde: Seaweed, food, medicine, and the peopling of South America. Science 320, 784– 786 (2008). 18467586 source
Interpretationreasoning
People must have been in North America ≥14.2 ka ago.
“indicating that people must have been in North America ≥14.2 ka ago”
Quote in the paperSubstantial claim
Premisereasoning
Archaeological studies over the last 25 years show that people successfully occupied the Americas ~14 to ~15 ka ago.
“Archaeological studies over the last 25 years show that people successfully occupied the Americas ~14 to ~15 ka ago, in agreement with the genetic estimates.”
Quote in the paperNot a substantial claim
Premisecitation
Genetic studies of modern Native Americans and prehistoric skeletons show that the initial movement of people south of the continental ice sheets occurred as early as ~15 to ~16 ka ago.
“genetic studies of modern Native Americans and prehistoric skeletons have shown that the initial movement of people south of the continental ice sheets occurred as early as ~15 to ~16 ka ago”
Quote in the paperNot a substantial claim0 of 2 sources checked
- cites [1] Moreno-Mayar J. V., Potter B. A., Vinner L., Steinrücken M., Rasmussen S., Terhorst J., Kamm J. A., Albrechtsen A., Malaspinas A.-S., Sikora M., Reuther J. D., Irish J. D., Malhi R. S., Orlando L., Song Y. S., Nielsen R., Meltzer D. J., Willerslev E., Terminal Pleistocene Alaskan genome reveals first founding population of native Americans. Nature 553, 203– 207 (2018). 29323294 source
- cites [2] Scheib C. L., Hongjie L., Desai T., Link V., Kendall C., Dewar G., Griffith P. W., Mörseburg A., Johnson J. R., Potter A., Kerr S. L., Endicott P., Lindo J., Haber M., Xue Y., Tyler-Smith C., Sandhu M. S., Lorenz J. G., Randall T. D., Faltyskova Z., Pagani L., Danecek P., O’Connell T. C., Martz P., Boraas A. S., Byrd B. F., Leventhal A., Cambra R., Williamson R., Lessage L., Holguin B., Ygnacio-De Soto E., Rosas J., Metspalu M., Stock J. T., Manica A., Scally A., Wegmann D., Malhi R. S., Kivisild T., Ancient human parallel lineages within North America contributed to a coastal expansion. Scien source
Premisecitation
Mixing of Late Prehistoric and Late Archaic point types in central Texas sites is common because of repeated use of cooking features during the Late Holocene.
“This type of mixing of Late Prehistoric and Late Archaic point types in central Texas sites is common because of repeated use of cooking features during the Late Holocene [e.g., (18, 20)].”
Quote in the paperNot a substantial claim0 of 2 sources checked
- cites [18] M. B. Collins, Archeology in Central Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 101–126.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [20] M. B. Collins, G. L. Bailey, N. A. Kenmotsu, F. A. Weir, Wilson-Leonard: An 11,000-year Archeological Record of Hunter-Gatherers in Central Texas (Studies in Archeology 31, Texas Archaeological Research Laboratory, University of Texas, 1998).
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Interpretationown data
The broken triangular lanceolate point lacks its distal tip due to a diagonal snap fracture that probably resulted from impact.
“This point lacks the distal tip due to a diagonal snap fracture that probably resulted from impact.”
Quote in the paperNot a substantial claim
Premisecitation
Dalton/Dalton series points are radiocarbon dated elsewhere to between ~11.2 and ~12 ka ago.
“Near and at the base of the Late Paleoindian zone at the Friedkin site are Dalton/Dalton series points that are radiocarbon dated elsewhere to between ~11.2 and ~12 ka ago (18, 22, 23).”
Quote in the paperNot a substantial claim0 of 3 sources checked
- cites [18] M. B. Collins, Archeology in Central Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 101–126.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [22] C. B. Bousman, B. W. Baker, and A. C. Kerr, Paleoindian Archeology in Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 15–97.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [23] Jennings T. A., Smallwood A. M., Waters M. R., Exploring late Paleoindian and early Archaic unfluted lanceolate point classification in the Southern Plains. North Am. Archaeol. 36, 243– 265 (2015). source
Premisecitation
Previous studies of the geology, pedology, micromorphology, and magnetic properties of the site's sediments show that the deposits at the Friedkin site are minimally disturbed by postdepositional processes.
“Previous studies of the geology, pedology, micromorphology, and magnetic properties of the site’s sediments show that the deposits at the Friedkin site are minimally disturbed by postdepositional processes (11, 16, 17).”
Quote in the paperSubstantial claim0 of 3 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
- cites [16] Driese S. G., Nordt L. C., Waters M. R., Keene J. L., Analysis of site formation history and potential disturbance of stratigraphic context in Vertisols at the Debra L. Friedkin archaeological site in central Texas, USA. Geoarchaeology 28, 221– 248 (2013). source
- cites [17] Lindquist A. K., Feinberg J. M., Waters M. R., Rock magnetic properties of a soil developed on an alluvial deposit at Buttermilk Creek, Texas, USA. Geochem. Geophys. Geosyst. 12, 1– 11 (2011). source
Study design and conductreasoning
The OSL dating method was used to determine the age of the artifacts at the Friedkin site by dating the floodplain sediments that bury them.
“Instead, the OSL dating method was used to determine the age of the artifacts at the Friedkin site by dating the floodplain sediments that bury them.”
Quote in the paperSubstantial claim
- Rests on an assumption: According to the geological principle of inclusions, any items, such as artifacts, in an undisturbed sedimentary deposit are at least as old as the sediments that contain them.
Interpretationreasoning
Since burial, the cultural zones at the Friedkin site have remained intact with minimal disturbance.
“Since burial, these zones have remained intact with minimal disturbance.”
Quote in the paperSubstantial claim
Premisecitation
Golondrina, St. Mary Hall, and Angostura types commonly co-occur at sites such as the Wilson-Leonard site, located 40 km from the Friedkin site, where they overlap in deposits radiocarbon dated between ~9.7 and ~11.1 ka ago.
“These types commonly co-occur at sites such as the Wilson-Leonard site, located 40 km from the Friedkin site, where Golondrina, St. Mary Hall, and Angostura types overlap in deposits radiocarbon dated between ~9.7 and ~11.1 ka ago (20).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [20] M. B. Collins, G. L. Bailey, N. A. Kenmotsu, F. A. Weir, Wilson-Leonard: An 11,000-year Archeological Record of Hunter-Gatherers in Central Texas (Studies in Archeology 31, Texas Archaeological Research Laboratory, University of Texas, 1998).
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Interpretationcitation
This assemblage compares well with the pre-Clovis assemblage from the Gault site.
“This assemblage compares well with the pre-Clovis assemblage from the Gault site (15).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [15] Williams T. J., Collins M. B., Rodrigues K., Rink W. J., Velchoff N., Keen-Zebert A., Gilmer A., Frederick C. D., Ayala S. J., Prewitt E. R., Evidence of an early projectile point technology in North America at the Gault site, Texas, USA. Sci. Adv. 4, eaar5954 (2018). 30009257 PMC6040843 source
Interpretationreasoning
There were sequential occupations on the Buttermilk Creek floodplain that were incrementally buried over time by sediment during repeated overbank events over the last 13 ka.
“This shows that there were sequential occupations on the Buttermilk Creek floodplain that were incrementally buried over time by sediment during repeated overbank events over the last 13 ka.”
Quote in the paperSubstantial claim
Interpretationcitation
The lanceolate stemmed points of the Buttermilk Creek Complex closely resemble an undated Texas projectile point type defined as "Early Stemmed Lanceolate".
“The lanceolate stemmed points of the Buttermilk Creek Complex closely resemble an undated Texas projectile point type defined as “Early Stemmed Lanceolate” (25).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [25] E. S. Turner, T. R. Hester, R. L. McReynolds, Stone Artifacts of Texas Indians (Taylor Trade Publishing, 2011).
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Interpretationreasoning
The superposition of cultural time horizons described for the Late Prehistoric through Clovis horizons at the site, based on the distribution of 130 time-diagnostic artifacts, shows that downward movement of large artifacts, such as projectile points, did not occur.
“The superposition of cultural time horizons described for the Late Prehistoric through Clovis horizons at the site based on the distribution of 130 time-diagnostic artifacts shows that downward movement of large artifacts, such as projectile points, did not occur.”
Quote in the paperSubstantial claim
Interpretationown data
These distributions show that artifacts have remained in their original context, albeit on a sloping surface in the 2015-2016 block excavation.
“These distributions again show that artifacts have remained in their original context, albeit on a sloping surface in the 2015–2016 block excavation.”
Quote in the paperSubstantial claim
Interpretationcitation
These people likely arrived by traversing the Pacific coast using watercraft.
“These people likely arrived by traversing the Pacific coast using watercraft (Fig. 6A) (10, 32).”
Quote in the paperNot a substantial claim0 of 2 sources checked
- cites [10] Beck C., Jones G. T., Clovis and Western Stemmed: Population migration and the meeting of two technologies in the Intermountain West. Am. Antiq. 75, 81– 116 (2010). source
- cites [32] Lesnek A. J., Briner J. P., Lindqvist C., Baichtal J. F., Heaton T. H., Deglaciation of the Pacific coastal corridor directly preceded the human colonization of the Americas. Sci. Adv. 4, eaar5040 (2018). 29854947 PMC5976267 source
Premisecitation
The Pacific coastal corridor would have been open for migration by ~16 ka ago as the Cordilleran Ice Sheet retreated and exposed tracks of land along the coast.
“This corridor would have been open for migration by ~16 ka ago as the Cordilleran Ice Sheet retreated and exposed tracks of land along the coast (32).”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [32] Lesnek A. J., Briner J. P., Lindqvist C., Baichtal J. F., Heaton T. H., Deglaciation of the Pacific coastal corridor directly preceded the human colonization of the Americas. Sci. Adv. 4, eaar5040 (2018). 29854947 PMC5976267 source
Interpretationreasoning
There is an in situ cultural horizon predating Clovis at the Friedkin site.
“and that there is an in situ cultural horizon predating Clovis at the site.”
Quote in the paperSubstantial claim
Interpretationown data
The multiple modes of artifact concentrations suggest changes in local lithic reduction activities through time.
“which suggest changes in local lithic reduction activities through time.”
Quote in the paperNot a substantial claim
Interpretationreasoning
The OSL ages from the Friedkin site are accurate.
“that the OSL ages from the site are accurate”
Quote in the paperSubstantial claim
- The authors state this as an assumption: The U and Th decay series are in secular equilibrium in the dated sediments.
- Rests on an assumption: The moisture content of the dated sediments during burial was similar to that of the nearby pedons used to derive it.
- Rests on an assumption: The cosmic ray dose rate component can be estimated from the current depth of burial.
Study design and conductown data
There was concordance (±10%) with the known dose for preheat temperatures between 160° and 200°C.
“There was concordance (±10%) with the known dose for preheat temperatures between 160° and 200°C with a used initial preheat temperature of 180°C for 10 s in the SAR protocols (fig. S3).”
Quote in the paperSubstantial claim
Interpretationreasoning
The general increase in total lithic tools and debitage at the Friedkin site reflects a continuous increase in lithic reduction activity from the Late Pleistocene through the Holocene.
“that appears to reflect a continuous increase in lithic reduction activity from the Late Pleistocene through the Holocene”
Quote in the paperNot a substantial claim
Interpretationreasoning
The evidence from Friedkin, Gault, and other sites suggests that the earliest known people to enter the Americas were using stemmed points.
“The evidence from Friedkin, Gault, and other sites suggests that the earliest known people to enter the Americas were using stemmed points.”
Quote in the paperSubstantial claim
Interpretationcitation
Stemmed points may date to the earliest occupation at Paisley Caves.
“This, combined with the lack of diagnostic Clovis technology in the site assemblage, suggests that stemmed points may date to the earliest occupation at Paisley Caves (9).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [9] Jenkins D. L., Davis L. G., Stafford T. W. Jr, Campos P. F., Hockett B., Jones G. T., Cummings L. S., Yost C., Connolly T. J., Yohe R. M. II, Gibbons S. C., Raghavan M., Rasmussen M., Paijmans J. L. A., Hofreiter M., Kemp B. M., Barta J. L., Monroe C., Gilbert M. T. P., Willerslev E., Clovis age Western Stemmed projectile points and human coprolites at the Paisley Caves. Science 337, 223– 228 (2012). 22798611 source
Premisecitation
The interior corridor between the Cordilleran and Laurentide ice sheets did not open until ~14 ka ago.
“The interior corridor between the Cordilleran and Laurentide ice sheets did not open until ~14 ka ago”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [32] Lesnek A. J., Briner J. P., Lindqvist C., Baichtal J. F., Heaton T. H., Deglaciation of the Pacific coastal corridor directly preceded the human colonization of the Americas. Sci. Adv. 4, eaar5040 (2018). 29854947 PMC5976267 source
Interpretationreasoning
Variation in the number of formal tools with depth demonstrates the presence of intact cultural horizons at the Debra L. Friedkin site.
“Variation in the number of formal tools with depth also demonstrates the presence of intact cultural horizons at the Friedkin site.”
Quote in the paperSubstantial claim
Study design and conductown data
All four OSL columns are internally consistent with very good agreement levels.
“All four columns are internally consistent with very good agreement levels.”
Quote in the paperSubstantial claim
Study design and conductcitation
The 4- to 11-μm quartz fraction had yielded previously accurate OSL ages.
“we focused on OSL dating the 4- to 11-μm quartz fraction, which had yielded previously accurate ages (11, 13).”
Quote in the paperSubstantial claim0 of 2 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
- cites [13] Forman S. L., Waters M. R., Optically stimulated luminescence dating and the peopling of the Americas. PaleoAmerica 2, 6– 10 (2016). source
- The authors state this as an assumption: The U and Th decay series are in secular equilibrium in the dated sediments.
- Rests on an assumption: The moisture content of the dated sediments during burial was similar to that of the nearby pedons used to derive it.
- Rests on an assumption: The cosmic ray dose rate component can be estimated from the current depth of burial.
Interpretationreasoning
In short, 130 time-diagnostic artifacts within the Late Prehistoric to Clovis horizons, coupled with all other previous studies, show that downward movement of artifacts did not take place at the site.
“In short, 130 time-diagnostic artifacts within the Late Prehistoric to Clovis horizons, coupled with all other previous studies (11, 16, 17), show that downward movement of artifacts did not take place at the site.”
Quote in the paperSubstantial claim0 of 3 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
- cites [16] Driese S. G., Nordt L. C., Waters M. R., Keene J. L., Analysis of site formation history and potential disturbance of stratigraphic context in Vertisols at the Debra L. Friedkin archaeological site in central Texas, USA. Geoarchaeology 28, 221– 248 (2013). source
- cites [17] Lindquist A. K., Feinberg J. M., Waters M. R., Rock magnetic properties of a soil developed on an alluvial deposit at Buttermilk Creek, Texas, USA. Geochem. Geophys. Geosyst. 12, 1– 11 (2011). source
Premisecitation
Bison and other animals were passing through the interior corridor by ~13 ka ago.
“and bison and other animals were passing through the corridor by ~13 ka ago (32).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [32] Lesnek A. J., Briner J. P., Lindqvist C., Baichtal J. F., Heaton T. H., Deglaciation of the Pacific coastal corridor directly preceded the human colonization of the Americas. Sci. Adv. 4, eaar5040 (2018). 29854947 PMC5976267 source
Interpretationown data
There has been minimal to no movement of artifacts between cultural zones at the Friedkin site.
“These lines of evidence demonstrate that there has been minimal to no movement of artifacts between cultural zones at the site”
Quote in the paperSubstantial claim
Interpretationreasoning
The ice-free corridor did not open soon enough to explain the presence of people south of the ice before ~14 ka ago.
“The ice-free corridor did not open soon enough to explain the presence of people south of the ice before ~14 ka ago.”
Quote in the paperSubstantial claim
Premisecitation
At Santa Isabel Iztapan II, two stemmed points were associated with butchered mammoth bones in the same lacustrine sediments.
“Four hundred meters away, at Santa Isabel Iztapan II, two stemmed points (Fig. 5, M and N) were associated with butchered mammoth bones in the same lacustrine sediments (29).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [29] Aveleyra Arroyo de Anda L., Maldonado-Koerdell M., Association of artifacts with mammoth in the Valley of Mexico. Am. Antiq. 18, 332– 340 (1953). source
Premisecitation
In Mexico, a stemmed projectile point along with other artifacts was associated with the bones of a single mammoth buried in undisturbed lacustrine sediments at Santa Isabel Iztapan I.
“In Mexico, a stemmed projectile point (Fig. 5O), along with other artifacts, was associated with the bones of a single mammoth buried in undisturbed lacustrine sediments at Santa Isabel Iztapan I (Fig. 6A) (29, 30).”
Quote in the paperNot a substantial claim0 of 2 sources checked
- cites [29] Aveleyra Arroyo de Anda L., Maldonado-Koerdell M., Association of artifacts with mammoth in the Valley of Mexico. Am. Antiq. 18, 332– 340 (1953). source
- cites [30] Gonzalez S., Huddart D., Israde-Alcántara I., Domínguez-Vázquez G., Bischoff J., Felstead N., Paleoindian sites from the Basin of Mexico: Evidence from stratigraphy, tephrochronology and dating. Quat. Int. 363, 4– 19 (2015). source
Premisecitation
Western Stemmed Tradition projectile points are at least contemporaneous with Clovis, dated to ~12.7 to ~13 ka ago.
“These Western Stemmed Tradition projectile points are at least contemporaneous with Clovis, dated to ~12.7 to ~13 ka ago (9).”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [9] Jenkins D. L., Davis L. G., Stafford T. W. Jr, Campos P. F., Hockett B., Jones G. T., Cummings L. S., Yost C., Connolly T. J., Yohe R. M. II, Gibbons S. C., Raghavan M., Rasmussen M., Paijmans J. L. A., Hofreiter M., Kemp B. M., Barta J. L., Monroe C., Gilbert M. T. P., Willerslev E., Clovis age Western Stemmed projectile points and human coprolites at the Paisley Caves. Science 337, 223– 228 (2012). 22798611 source
Interpretationown data
Two smaller peaks below the Folsom and Clovis horizon, at 90.375 to 90.35 m AD and 90.30 to 90.275 m AD, seem to reflect separate occupation episodes in the Buttermilk Creek Complex horizon.
“with two smaller peaks below this, at 90.375 to 90.35 m AD and 90.30 to 90.275 m AD, that seem to reflect separate occupation episodes in the Buttermilk Creek Complex horizon.”
Quote in the paperNot a substantial claim
Premisecitation
Along Buttermilk Creek, in similar deposits just 250 m upstream of Block A at the Friedkin site, stemmed projectile points dated to ~16 ka ago are reported below a Clovis horizon at Area 15 of the Gault site, Texas.
“Also, along Buttermilk Creek, in similar deposits just 250 m upstream of Block A at the Friedkin site, stemmed projectile points dated to ~16 ka ago are reported below a Clovis horizon at Area 15 of the Gault site, Texas (15).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [15] Williams T. J., Collins M. B., Rodrigues K., Rink W. J., Velchoff N., Keen-Zebert A., Gilmer A., Frederick C. D., Ayala S. J., Prewitt E. R., Evidence of an early projectile point technology in North America at the Gault site, Texas, USA. Sci. Adv. 4, eaar5954 (2018). 30009257 PMC6040843 source

It may state two separate claims as one. 43
Probably not a substantial claim. 22

It may state two separate claims as one.
Premisecitation
Humans were present in North America during the period ~14 to ~15 ka ago, as documented by archaeological evidence radiocarbon dated to ~14.6 ka at Page-Ladson, Florida; ~14.2 ka at Paisley Caves, Oregon; ~14.2 and ~14.8 ka at Schaefer and Hebior, Wisconsin; and ~13.8 ka at Manis, Washington.
“In North America, humans were present during the period ~14 to ~15 ka ago, as documented by archaeological evidence radiocarbon dated to ~14.6 ka ago at Page-Ladson, Florida (4); ~14.2 ka ago at Paisley Caves, Oregon (5); ~14.2 and ~14.8 ka ago at Schaefer and Hebior, Wisconsin (6, 7); and ~13.8 ka ago at Manis, Washington (8).”
Quote in the paperNot a substantial claim2 of 4 sources checked
- cites [4] Halligan J. J., Waters M. R., Perrotti A., Owens I. J., Feinberg J. M., Bourne M. D., Fenerty B., Winsborough B., Carlson D., Fisher D. C., Stafford T. W. Jr, Dunbar J. S., Pre-Clovis occupation 14,550 years ago at the Page-Ladson site, Florida, and the peopling of the Americas. Sci. Adv. 2, e1600375 (2016). 27386553 PMC4928949 source
- cites [5] Gilbert M. T. P., Jenkins D. L., Götherstrom A., Naveran N., Sanchez J. J., Hofreiter M., Thomsen P. F., Binladen J., Higham T. F. G., Yohne R. M. II, Parr R., Cummings L. S., Willerslev E., DNA from pre-Clovis human coprolites in Oregon, North America. Science 320, 786– 789 (2008). 18388261 source
  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
  Experimental — accuracy not yet measured
- cites [6] Joyce D. J., Chronology and new research on the Schaefer mammoth (Mammuthus primigenius) site, Kenosha County, Wisconsin, USA. Quat. Int. 142–143, 44– 57 (2006). source
- cites [7] M. R. Waters, T. W. Stafford, The First Americans: A review of the evidence for the late-Pleistocene peopling of the Americas, in Paleoamerican Odyssey, K. E. Graf, C. V. Ketron, M. R. Waters, Eds. (Texas A&M Univ. Press, 2014), pp. 541–560.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
It may state two separate claims as one.
Findingnone given
Stemmed projectile points at the Debra L. Friedkin site are ~13,500 to ~15,500 years old and lie stratigraphically below ~13,000-year-old Clovis artifacts.
“Stemmed projectile points are ~13,500 to ~15,500 years old and lie stratigraphically below ~13,000-year-old Clovis artifacts.”
Quote in the paperSubstantial claim
It may state two separate claims as one.
Findingown data
Most flake scars on the late-stage bifaces terminate at the midline, but five bifaces show flakes crossing over the midline (overface flaking) and two display a rolled edge from an overshot flake removal; two overshot flakes were found in the same deposits.
“Most flake scars on these bifaces terminate at the midline, but five bifaces show flakes crossing over the midline of the biface (overface flaking) and two display a rolled edge from an overshot flake removal. Two overshot flakes were found in the same deposits.”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
Forty late-stage biface fragments were found in the ~13.5- to ~15.5-thousand-year-old sediments; of these, 13 are large enough to provide insights into the production of stemmed lanceolate points.
“Forty late-stage biface fragments were found in the ~13.5- to ~15.5-thousand-year-old sediments. Of these, 13 are large enough to provide insights into the production of stemmed lanceolate points (fig. S7 and table S3).”
Quote in the paperSubstantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Findingown data
Near the top of the Folsom-Clovis zone are a Folsom point fragment and two late-stage Folsom preform flute failures, separated up to 9 m horizontally but only 1.7 cm vertically.
“Near the top of this zone are a Folsom point fragment and two late-stage Folsom preform flute failures (fig. S4). These Folsom artifacts are separated up to 9 m horizontally (Fig. 4F) but only 1.7 cm vertically.”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
Both pre-13-thousand-year-old and Clovis bifaces at the Friedkin site exhibit overface and overshot flaking, reflecting similar biface thinning strategies; however, these flaking techniques were used with greater frequency to produce Clovis preforms.
“Both exhibit overface and overshot flaking, reflecting similar biface thinning strategies; however, these flaking techniques were used with greater frequency to produce Clovis preforms.”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
The pre-13-thousand-year-old bifaces are predominately made on large flake blanks, whereas the Clovis bifaces were made from both nodules and flake blanks.
“The pre–13-thousand-year-old bifaces are predominately made on large flake blanks, whereas the Clovis bifaces were made from both nodules and flake blanks.”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
OSL ages ranging from 11,210 ± 405 yr B.P. to 11,980 ± 555 yr B.P. occur in the zone with the Dalton/Dalton series points and agree well with the known age for Dalton at other sites.
“The OSL ages ranging from 11,210 ± 405 yr B.P. (BG4206) to 11,980 ± 555 yr B.P. (UIC2048) occur in the zone with the Dalton/Dalton series points (Figs. 2 and 3) and again agree well with the known age for Dalton at other sites.”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
The ~13.5- to ~15.5-thousand-year-old assemblage at the Friedkin site also includes blade segments, bladelets, scrapers, bifacial discoidal cores, and snap fracture tools (radial and bend break) most commonly made on flakes but also bifaces, retouched flakes, expedient tools, and ground hematite.
“In addition to the points and other bifaces, the ~13.5- to ~15.5-thousand-year-old assemblage at the Friedkin site also includes blade segments, bladelets, scrapers, bifacial discoidal cores, and snap fracture tools (radial and bend break) most commonly made on flakes but also bifaces, retouched flakes, expedient tools, and ground hematite.”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
In the upper 0.8 to 1.1 m of the floodplain sequence at Block A, the authors recovered over 639,000 artifacts, including over 4600 tools, of which 130 are time diagnostic.
“In the upper 0.8 to 1.1 m of the floodplain sequence at Block A, we recovered over 639,000 artifacts, including over 4600 tools, of which 130 are time diagnostic (mostly projectile points).”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
The other point fragments (AM12170-1, AM6233-1, AM8380-3, and AM8286-16) occur 2.4 to 5.3 m from the nearest OSL column and lie in the horizon dated between ~13.5 and ~15.5 ka ago.
“The other point fragments (AM12170-1, AM6233-1, AM8380-3, and AM8286-16) occur 2.4 to 5.3 m from the nearest OSL column. These points lie in the horizon dated between ~13.5 and ~15.5 ka ago.”
Quote in the paperSubstantial claim
It may state two separate claims as one.
Findingown data
The four zones occur in chronological order, with Late Prehistoric and Late Archaic artifacts near the surface, followed by a zone with only Middle Archaic and Early Archaic artifacts, then a deeper zone with Late Paleoindian point types, and below this a zone containing only Folsom and Clovis artifacts.
“These zones occur in chronological order, with Late Prehistoric and Late Archaic artifacts occurring near the surface, followed by a zone with only Middle Archaic and Early Archaic artifacts, then by a deeper zone with Late Paleoindian point types, and below this a zone containing only Folsom and Clovis artifacts (Figs. 2 and 3).”
Quote in the paperSubstantial claim
It may state two separate claims as one.
Findingown data
Angostura points are associated with all six OSL ages from the Middle Archaic and Early Archaic horizon; four ages overlap with the known minimum age for Angostura (~8.6 ka ago), but two OSL ages appear too young for Angostura.
“Angostura points are associated with all six OSL ages; four ages overlap with the known minimum age for Angostura (~8.6 ka ago), but two OSL ages appear too young for Angostura.”
Quote in the paperNot a substantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Findingown data
Forty-four Late Prehistoric and Late Archaic points are in chronological order.
“Forty-four Late Prehistoric and Late Archaic points are in chronological order (Figs. 2 and 3).”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
Three OSL ages temporally bracket the complete point (AM9875-2): the two ages below the point are 18,480 ± 880 yr B.P. and 19,410 ± 650 yr B.P., and, at 3 cm above this point, the age is 15,190 ± 465 yr B.P.
“Three OSL ages temporally bracket the complete point (AM9875-2) that rested horizontally on older floodplain clays; the two ages below the point are 18,480 ± 880 yr B.P. (BG3994) and 19,410 ± 650 yr B.P. (BG4076), and, at 3 cm above this point, the age is 15,190 ± 465 yr B.P. (BG3995).”
Quote in the paperSubstantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Findingown data
Nine channel flakes were recovered; seven were found within the Folsom and Clovis zone, one was found <2.5 cm below the lower boundary, and one was found <5 cm above the upper contact of this zone.
“In addition, nine channel flakes were recovered. Seven were found within the Folsom and Clovis zone, one was found <2.5 cm below the lower boundary, and one was found <5 cm above the upper contact of this zone (Figs. 2 and 3).”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingown data
The broken triangular lanceolate point was found at the same elevation and 1 m south of the OSL age 14,270 ± 365 yr B.P.; a second age 13,625 ± 455 yr B.P. was obtained 4.5 cm above the point.
“This point was found at the same elevation and 1 m south of the OSL age 14,270 ± 365 yr B.P. (BG4017). A second age 13,625 ± 455 yr B.P. (BG4019) was obtained 4.5 cm above the point.”
Quote in the paperSubstantial claim
It may state two separate claims as one.
Findingown data
Correlation of Bayesian-modeled OSL ages and time-diagnostic artifacts shows that, in most areas of the site, floodplain sediments were horizontally deposited, but slope slightly upward at the northwest end of the 2007 excavation area and downward at the southeast end of the 2016 excavation area of Block A.
“Correlation of Bayesian-modeled OSL ages and time-diagnostic artifacts shows that, in most areas of the site, floodplain sediments were horizontally deposited, but slope slightly upward at the northwest end of the 2007 excavation area and downward at the southeast end of the 2016 excavation area of Block A (Figs. 1 to 3).”
Quote in the paperNot a substantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Findingown data
In the Middle Archaic and Early Archaic zone at the Friedkin site, 15 time-diagnostic Early Archaic projectile points were recovered.
“In the Middle Archaic and Early Archaic zone at the Friedkin site, 15 time-diagnostic Early Archaic projectile points were recovered (Figs. 2 to 4).”
Quote in the paperNot a substantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Findingcitation
Thirty-eight OSL ages were previously published, and 32 new OSL ages were obtained in 2015 and 2016.
“Thirty-eight OSL ages were previously published (11). Here, we present 32 new OSL ages obtained in 2015 and 2016 (table S1).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
It may state two separate claims as one.
Findingcitation
The ages from the Folsom-Clovis zone fall within the known age range for Folsom (~12.2 to 12.7 ka ago) and Clovis (~12.7 to ~13 ka ago).
“These ages fall within the known age range for Folsom (~12.2 to 12.7 ka ago) and Clovis (~12.7 to ~13 ka ago) (7).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [7] M. R. Waters, T. W. Stafford, The First Americans: A review of the evidence for the late-Pleistocene peopling of the Americas, in Paleoamerican Odyssey, K. E. Graf, C. V. Ketron, M. R. Waters, Eds. (Texas A&M Univ. Press, 2014), pp. 541–560.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
It may state two separate claims as one.
Findingown data
The Clovis point base (AM12018-1) is within 20 cm of the 2016 column of OSL ages and is bracketed by ages of 12,500 ± 480 yr B.P. and 12,950 ± 480 yr B.P.
“The Clovis point base (AM12018-1) is within 20 cm of the 2016 column of OSL ages and is bracketed by ages of 12,500 ± 480 yr B.P. (BG4209) and 12,950 ± 480 yr B.P. (BG4218).”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Findingcitation
The deepest floodplain clays are OSL dated to >16 ka ago (n = 13) and have no in situ artifacts.
“The deepest floodplain clays are OSL dated to >16 ka ago (n = 13) and have no in situ artifacts (Figs. 2 and 3 and table S2) (11).”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
It may state two separate claims as one.
Findingown data
The Late Paleoindian zone at the Friedkin site contains five Angostura, five St. Mary Hall, nine Golondrina, and five Dalton/Dalton series points.
“The Late Paleoindian zone at the Friedkin site contains five Angostura, five St. Mary Hall, nine Golondrina, and five Dalton/Dalton series points (Figs. 2 and 4).”
Quote in the paperNot a substantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Findingown data
Analysis of the 2016 column produced agreement indices of 187.1/179.8 with no outliers.
“Analysis of the 2016 column produced agreement indices of 187.1/179.8 with no outliers.”
Quote in the paperNot a substantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Findingown data
The 2008 and 2015 columns combined into a single Bayesian age model resulted in model agreement values of 182.3/185.7 with two outliers (UIC2361 and UIC2349).
“The 2008 and 2015 columns were combined into a single Bayesian age model that resulted in model agreement values of 182.3/185.7 with two outliers (UIC2361 and UIC2349).”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Premisecitation
The first recognizable and widespread North American archaeological traditions appeared ~13 ka ago, with people making lanceolate fluted points in central and eastern North America (Clovis Tradition) and others using stemmed projectile points in unglaciated western North America (Western Stemmed Tradition).
“It was not until ~13 ka ago that the first recognizable and widespread North American archaeological traditions appeared, with people making lanceolate fluted points in central and eastern North America (Clovis Tradition) and others using stemmed projectile points in unglaciated western North America (Western Stemmed Tradition) (9, 10).”
Quote in the paperSubstantial claim0 of 2 sources checked
- cites [9] Jenkins D. L., Davis L. G., Stafford T. W. Jr, Campos P. F., Hockett B., Jones G. T., Cummings L. S., Yost C., Connolly T. J., Yohe R. M. II, Gibbons S. C., Raghavan M., Rasmussen M., Paijmans J. L. A., Hofreiter M., Kemp B. M., Barta J. L., Monroe C., Gilbert M. T. P., Willerslev E., Clovis age Western Stemmed projectile points and human coprolites at the Paisley Caves. Science 337, 223– 228 (2012). 22798611 source
- cites [10] Beck C., Jones G. T., Clovis and Western Stemmed: Population migration and the meeting of two technologies in the Intermountain West. Am. Antiq. 75, 81– 116 (2010). source
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Premisecitation
There is genetic continuity between the first immigrants to enter the Americas and modern Native Americans.
“there is genetic continuity between the first immigrants to enter the Americas and modern Native Americans (1, 2)”
Quote in the paperNot a substantial claim0 of 2 sources checked
- cites [1] Moreno-Mayar J. V., Potter B. A., Vinner L., Steinrücken M., Rasmussen S., Terhorst J., Kamm J. A., Albrechtsen A., Malaspinas A.-S., Sikora M., Reuther J. D., Irish J. D., Malhi R. S., Orlando L., Song Y. S., Nielsen R., Meltzer D. J., Willerslev E., Terminal Pleistocene Alaskan genome reveals first founding population of native Americans. Nature 553, 203– 207 (2018). 29323294 source
- cites [2] Scheib C. L., Hongjie L., Desai T., Link V., Kendall C., Dewar G., Griffith P. W., Mörseburg A., Johnson J. R., Potter A., Kerr S. L., Endicott P., Lindo J., Haber M., Xue Y., Tyler-Smith C., Sandhu M. S., Lorenz J. G., Randall T. D., Faltyskova Z., Pagani L., Danecek P., O’Connell T. C., Martz P., Boraas A. S., Byrd B. F., Leventhal A., Cambra R., Williamson R., Lessage L., Holguin B., Ygnacio-De Soto E., Rosas J., Metspalu M., Stock J. T., Manica A., Scally A., Wegmann D., Malhi R. S., Kivisild T., Ancient human parallel lineages within North America contributed to a coastal expansion. Scien source
It may state two separate claims as one.
Premisenone given
The artifact assemblages from the ~14- to ~15-thousand-year-old North American sites are small and nondiagnostic, and lithic projectile points are absent.
“However, the artifact assemblages from these ~14- to ~15-thousand-year-old North American sites are small and nondiagnostic, and lithic projectile points are absent.”
Quote in the paperSubstantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Premisecitation
Luminescence dating has been used to successfully date archaeological sites in North America such as the Clovis horizon at Pavo Real, Texas, and the Archaic, Paleoindian, and pre-Clovis horizons at the Gault site, Texas.
“Luminescence dating has also been used to successfully date archaeological sites in North America such as the Clovis horizon at Pavo Real, Texas, and the Archaic, Paleoindian, and pre-Clovis horizons at the Gault site, Texas (12, 14, 15).”
Quote in the paperNot a substantial claim0 of 3 sources checked
- cites [12] M. R. Waters, C. D. Pevny, D. L. Carlson, Clovis Lithic Technology: Investigation of a Stratified Workshop at the Gault Site, Texas (Texas A&M Univ. Press, 2011).
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [14] Rodrigues K., Rink W. J., Collins M. B., Williams T. J., Keen-Zebert A., Lόpez G. I., OSL ages of the Clovis, Late Paleoindian, and Archaic components at Area 15 of the Gault Site, Central Texas, U.S.A. J. Archaeol. Sci. Rep. 7, 94– 103 (2016). source
- cites [15] Williams T. J., Collins M. B., Rodrigues K., Rink W. J., Velchoff N., Keen-Zebert A., Gilmer A., Frederick C. D., Ayala S. J., Prewitt E. R., Evidence of an early projectile point technology in North America at the Gault site, Texas, USA. Sci. Adv. 4, eaar5954 (2018). 30009257 PMC6040843 source
It may state two separate claims as one.
Interpretationreasoning
All bifaces are plano-convex in cross section, indicating that lanceolate stemmed points were made from flake blanks that were bifacially reduced by lateral thinning.
“All bifaces are plano-convex in cross section, indicating that lanceolate stemmed points were made from flake blanks that were bifacially reduced by lateral thinning.”
Quote in the paperSubstantial claim
It may state two separate claims as one.
Premisecitation
The OSL method has been used for decades to date Late Quaternary deposits and has been shown to yield accurate ages; many tests have shown that OSL ages are in agreement with radiocarbon ages.
“The OSL method has been used for decades to date Late Quaternary deposits and has been shown to yield accurate ages; many tests have shown that OSL ages are in agreement with radiocarbon ages (13).”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [13] Forman S. L., Waters M. R., Optically stimulated luminescence dating and the peopling of the Americas. PaleoAmerica 2, 6– 10 (2016). source
It may state two separate claims as one.
Interpretationown data
Within the Late Prehistoric to Clovis horizons at the Friedkin site, the relative order of time-diagnostic artifacts matches the known cultural chronology for central Texas, and the known ages for time-diagnostic artifacts overlap with OSL ages.
“Overall, these results show that within the Late Prehistoric to Clovis horizons at the Friedkin site, the relative order of time-diagnostic artifacts matches the known cultural chronology for central Texas, and the known ages for time-diagnostic artifacts overlap with OSL ages.”
Quote in the paperSubstantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
Premisenone given
It is not uncommon for older projectile point types to be found in a younger cultural context because prehistoric people would sometimes pick up older points from the surface and bring them to their camps.
“It is not uncommon for older projectile point types to be found in a younger cultural context because prehistoric people would sometimes pick up older points from the surface and bring them to their camps.”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Interpretationown data
The association of Angostura points with two OSL ages that appear too young suggests that either the Angostura type extends later in time or some of the Angostura points at the Friedkin site may be intrusive into the youngest Early Archaic sediments.
“This suggests that either this type extends later in time or some of the Angostura points at the Friedkin site may be intrusive into the youngest Early Archaic sediments.”
Quote in the paperNot a substantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Premisecitation
In central Texas, the Late Prehistoric period postdates ~0.65 ka ago, and the Late Archaic period dates between ~0.65 and ~4.2 ka ago.
“In central Texas, the Late Prehistoric period postdates ~0.65 ka ago, and the Late Archaic period dates between ~0.65 and ~4.2 ka ago (18, 19).”
Quote in the paperNot a substantial claim0 of 2 sources checked
- cites [18] M. B. Collins, Archeology in Central Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 101–126.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [19] Lohse J., Black S. L., Cholak L. M., Toward an improved Archaic radiocarbon chronology for Central Texas. Bull. Texas Archeol. Soc. 85, 259– 287 (2014).
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Interpretationcitation
This assemblage, combined with the newly described projectile points, makes up the Buttermilk Creek Complex.
“This assemblage, combined with the newly described projectile points, makes up the Buttermilk Creek Complex (11, 24).”
Quote in the paperNot a substantial claim0 of 2 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
- cites [24] Jennings T. A., Waters M. R., Pre-Clovis lithic technology at the Debra L. Friedkin site, Texas: Comparisons to Clovis through site-level behavior, technological trait-list, and cladistics analysis. Am. Antiq. 79, 25– 44 (2014). source
It may state two separate claims as one.
Premisecitation
Below the Middle Archaic and Early Archaic zone is a 25-cm-thick zone with Late Paleoindian diagnostic artifacts, known to date ~9 to 12 ka ago in central Texas.
“Below the Middle Archaic and Early Archaic zone is a 25-cm-thick zone with Late Paleoindian diagnostic artifacts, known to date ~9 to 12 ka ago in central Texas (18, 20, 22, 23).”
Quote in the paperNot a substantial claim0 of 4 sources checked
- cites [18] M. B. Collins, Archeology in Central Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 101–126.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [20] M. B. Collins, G. L. Bailey, N. A. Kenmotsu, F. A. Weir, Wilson-Leonard: An 11,000-year Archeological Record of Hunter-Gatherers in Central Texas (Studies in Archeology 31, Texas Archaeological Research Laboratory, University of Texas, 1998).
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [22] C. B. Bousman, B. W. Baker, and A. C. Kerr, Paleoindian Archeology in Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 15–97.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [23] Jennings T. A., Smallwood A. M., Waters M. R., Exploring late Paleoindian and early Archaic unfluted lanceolate point classification in the Southern Plains. North Am. Archaeol. 36, 243– 265 (2015). source
It may state two separate claims as one.
Premisecitation
Angostura, St. Mary Hall, and Golondrina point types are poorly dated, but estimates place Golondrina at ~9.6 to ~11.2 ka ago, St. Mary Hall at ~9.8 to ~11.5 ka ago, and Angostura at ~8.6 to 10.4 ka ago.
“These types are poorly dated, but estimates place Golondrina at ~9.6 to ~11.2 ka ago, St. Mary Hall at ~9.8 to ~11.5 ka ago, and Angostura at ~8.6 to 10.4 ka ago (18, 22, 23).”
Quote in the paperNot a substantial claim0 of 3 sources checked
- cites [18] M. B. Collins, Archeology in Central Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 101–126.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [22] C. B. Bousman, B. W. Baker, and A. C. Kerr, Paleoindian Archeology in Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 15–97.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [23] Jennings T. A., Smallwood A. M., Waters M. R., Exploring late Paleoindian and early Archaic unfluted lanceolate point classification in the Southern Plains. North Am. Archaeol. 36, 243– 265 (2015). source
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Premisecitation
In central Texas, the Middle Archaic dates between ~4.2 and ~5.7 ka ago, and the Early Archaic dates from ~5.7 to ~8.6 ka ago.
“In central Texas, the Middle Archaic dates between ~4.2 and ~5.7 ka ago, and the Early Archaic dates from ~5.7 to ~8.6 ka ago (18–20).”
Quote in the paperNot a substantial claim0 of 3 sources checked
- cites [18] M. B. Collins, Archeology in Central Texas, in The Prehistory of Texas, T. K. Perttula, Ed. (Texas A&M Univ. Press, 2004), pp. 101–126.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [19] Lohse J., Black S. L., Cholak L. M., Toward an improved Archaic radiocarbon chronology for Central Texas. Bull. Texas Archeol. Soc. 85, 259– 287 (2014).
- cites [20] M. B. Collins, G. L. Bailey, N. A. Kenmotsu, F. A. Weir, Wilson-Leonard: An 11,000-year Archeological Record of Hunter-Gatherers in Central Texas (Studies in Archeology 31, Texas Archaeological Research Laboratory, University of Texas, 1998).
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
It may state two separate claims as one.
Study design and conductcitation
The sediments at the Friedkin site are ideal for OSL dating because of the low-energy fluvial depositional environment; slow incremental deposition and weak pedogenic alteration ensured solar resetting of sediment grains before burial, and after burial the sediments were minimally disturbed.
“The sediments at the Friedkin site are ideal for OSL dating because of the low-energy fluvial depositional environment. The slow incremental deposition on the floodplain and associated weak pedogenic alternation ensured solar resetting of sediment grains before burial. After burial, the sediments on the floodplain were minimally disturbed (11, 13, 16, 17).”
Quote in the paperSubstantial claim0 of 4 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
- cites [13] Forman S. L., Waters M. R., Optically stimulated luminescence dating and the peopling of the Americas. PaleoAmerica 2, 6– 10 (2016). source
- cites [16] Driese S. G., Nordt L. C., Waters M. R., Keene J. L., Analysis of site formation history and potential disturbance of stratigraphic context in Vertisols at the Debra L. Friedkin archaeological site in central Texas, USA. Geoarchaeology 28, 221– 248 (2013). source
- cites [17] Lindquist A. K., Feinberg J. M., Waters M. R., Rock magnetic properties of a soil developed on an alluvial deposit at Buttermilk Creek, Texas, USA. Geochem. Geophys. Geosyst. 12, 1– 11 (2011). source
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Premisecitation
At Cooper's Ferry, Idaho, stemmed points are reported to date to ~13.2 ka ago.
“At Cooper’s Ferry, Idaho, stemmed points are reported to date to ~13.2 ka ago (Fig. 6) (28), but additional chronological information is needed to confirm this proposed age.”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [28] Davis L. G., Nyers A. J., Willis S. C., Context, provenance, and technology of a Western Stemmed Tradition artifact cache from the Cooper’s Ferry site, Idaho. Am. Antiq. 79, 596– 615 (2014). source
It may state two separate claims as one.
Interpretationown data
The OSL ages associated with each cultural zone agree with the known age of the time-diagnostic artifacts found in each zone, demonstrating the accuracy of these ages.
“In addition, the OSL ages associated with each cultural zone agree with the known age of the time-diagnostic artifacts found in each zone, demonstrating the accuracy of these ages.”
Quote in the paperSubstantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Premisecitation
At Meadowcroft Rockshelter, Pennsylvania, the Miller point may be dated to ~14 ka ago.
“At Meadowcroft Rockshelter, Pennsylvania (Fig. 6A), the Miller point (Fig. 5P) with its subtle shoulder and short stem may be dated to ~14 ka ago (7), but this age remains to be confirmed.”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [7] M. R. Waters, T. W. Stafford, The First Americans: A review of the evidence for the late-Pleistocene peopling of the Americas, in Paleoamerican Odyssey, K. E. Graf, C. V. Ketron, M. R. Waters, Eds. (Texas A&M Univ. Press, 2014), pp. 541–560.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Study design and conductown data
The recycling ratio was 1.00 ± 0.05 in the dose reproducibility test.
“A test for dose reproducibility was also performed following procedures of (36) with the initial and final regenerative dose of 4.2 Gy (fig. S2), with the resultant recycling ratio of 1.00 ± 0.05.”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [36] Murray A. S., Wintle A. G., The single aliquot regenerative dose protocol: Potential for improvements in reliability. Radiat. Meas. 37, 377– 381 (2003). source
It may state two separate claims as one.
Study design and conductcitation
All resultant samples showed weak emissions with infrared excitation at or close to background counts, and the ratio of emissions from blue to infrared excitation of >20, indicating a spectrally pure quartz extract.
“All resultant samples showed weak emissions (<400 counts/s) with infrared excitation at or close to background counts, and the ratio of emissions from blue to infrared excitation of >20, indicating a spectrally pure quartz extract (35).”
Quote in the paperSubstantial claim0 of 1 sources checked
- cites [35] Duller G. A. T., Bøtter-Jensen L., Murray A. S., Combining infrared- and green-laser stimulation sources in single-grain luminescence measurements of feldspar and quartz. Radiat. Meas. 37, 543– 550 (2003). source
It may state two separate claims as one.
Study design and conductown data
De distributions were log normal and exhibited overdispersion values ≤20%, except for sample DF16-05.
“De distributions were log normal and exhibited overdispersion values ≤20%, except for sample DF16-05 (table S1 and figs. S1 and S2).”
Quote in the paperSubstantial claim
It may state two separate claims as one.
Interpretationcitation
Both models are compatible with the current human genetic evidence and what is known about the opening of the coastal and inland corridors.
“Both models are compatible with the current human genetic evidence and what is known about the opening of the coastal and inland corridors (1, 2, 32).”
Quote in the paperNot a substantial claim0 of 3 sources checked
- cites [1] Moreno-Mayar J. V., Potter B. A., Vinner L., Steinrücken M., Rasmussen S., Terhorst J., Kamm J. A., Albrechtsen A., Malaspinas A.-S., Sikora M., Reuther J. D., Irish J. D., Malhi R. S., Orlando L., Song Y. S., Nielsen R., Meltzer D. J., Willerslev E., Terminal Pleistocene Alaskan genome reveals first founding population of native Americans. Nature 553, 203– 207 (2018). 29323294 source
- cites [2] Scheib C. L., Hongjie L., Desai T., Link V., Kendall C., Dewar G., Griffith P. W., Mörseburg A., Johnson J. R., Potter A., Kerr S. L., Endicott P., Lindo J., Haber M., Xue Y., Tyler-Smith C., Sandhu M. S., Lorenz J. G., Randall T. D., Faltyskova Z., Pagani L., Danecek P., O’Connell T. C., Martz P., Boraas A. S., Byrd B. F., Leventhal A., Cambra R., Williamson R., Lessage L., Holguin B., Ygnacio-De Soto E., Rosas J., Metspalu M., Stock J. T., Manica A., Scally A., Wegmann D., Malhi R. S., Kivisild T., Ancient human parallel lineages within North America contributed to a coastal expansion. Scien source
- cites [32] Lesnek A. J., Briner J. P., Lindqvist C., Baichtal J. F., Heaton T. H., Deglaciation of the Pacific coastal corridor directly preceded the human colonization of the Americas. Sci. Adv. 4, eaar5040 (2018). 29854947 PMC5976267 source
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Premisecitation
The Iztapan sites fall between ~14.5 and ~10.8 ka ago based on dated tephra layers.
“The Iztapan sites are not directly dated, but dated tephra layers bracketing the mammoth remains and associated artifacts suggest that they fall between ~14.5 and ~10.8 ka ago (30).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [30] Gonzalez S., Huddart D., Israde-Alcántara I., Domínguez-Vázquez G., Bischoff J., Felstead N., Paleoindian sites from the Basin of Mexico: Evidence from stratigraphy, tephrochronology and dating. Quat. Int. 363, 4– 19 (2015). source
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Premisecitation
El Jobo and later stemmed Fishtail points became widespread across South America ~13 ka ago.
“with El Jobo and later stemmed Fishtail points becoming widespread across South America ~13 ka ago (31).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [31] N. Flegenheimer, L. Miotti, N. Mazzia, Rethinking early objects and landscapes in the Southern Cone: Fishtail-point concentrations in the Pampas and northern Patagonia, in Paleoamerican Odyssey, K. E. Graf, C. V. Ketron, M. R. Waters, Eds. (Texas A&M Univ. Press, 2014), pp. 359–376.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
It may state two separate claims as one.
Interpretationreasoning
The triangular lanceolate point form could have developed in situ from the earlier lanceolate stemmed point and could be the precursor to the lanceolate, fluted Clovis point.
“This form could have developed in situ from the earlier lanceolate stemmed point and could be the precursor to the lanceolate, fluted Clovis point.”
Quote in the paperSubstantial claim
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Interpretationreasoning
The continuous increase in lithic reduction activity at the Friedkin site is due to either increasing human populations or increasing site occupation span and decreasing mobility over time.
“because of either increasing human populations or increasing site occupation span and decreasing mobility over time (Fig. 4A).”
Quote in the paperNot a substantial claim
It may state two separate claims as one.
Interpretationcitation
Similarities exist between the bifaces and tool assemblages of the Buttermilk Creek Complex and Clovis and may suggest that Clovis emerged in situ from the Buttermilk Creek Complex.
“Similarities exist between the bifaces and tool assemblages of the Buttermilk Creek Complex and Clovis and may suggest that Clovis emerged in situ from the Buttermilk Creek Complex (11, 24).”
Quote in the paperSubstantial claim0 of 2 sources checked
- cites [11] Waters M. R., Forman S. L., Jennings T. A., Nordt L. C., Driese S. G., Feinberg J. M., Keene J. L., Halligan J., Lindquist A., Pierson J., Hallmark C. T., Collins M. B., Wiederhold J. E., The Buttermilk Creek complex and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331, 1599– 1603 (2011). 21436451 source
- cites [24] Jennings T. A., Waters M. R., Pre-Clovis lithic technology at the Debra L. Friedkin site, Texas: Comparisons to Clovis through site-level behavior, technological trait-list, and cladistics analysis. Am. Antiq. 79, 25– 44 (2014). source
Probably not a substantial claim. The paper’s conclusions may not depend on it.
Premisecitation
At Monte Verde, Chile, people used stemmed El Jobo projectile points by ~14.2 ka ago.
“At Monte Verde, Chile (Fig. 6A), people used stemmed El Jobo projectile points by ~14.2 ka ago (7)”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [7] M. R. Waters, T. W. Stafford, The First Americans: A review of the evidence for the late-Pleistocene peopling of the Americas, in Paleoamerican Odyssey, K. E. Graf, C. V. Ketron, M. R. Waters, Eds. (Texas A&M Univ. Press, 2014), pp. 541–560.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Probably not a substantial claim. The authors may not put it forward as true. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Interpretationcitation
The stemmed and lanceolate point traditions of North America may represent two separate human migrations that took different routes south of the continental ice sheets and accessed and settled different parts of the unglaciated continent at the end of the Pleistocene.
“Alternatively, the stemmed and lanceolate point traditions of North America may represent two separate human migrations that took different routes south of the continental ice sheets and accessed and settled different parts of the unglaciated continent at the end of the Pleistocene (Fig. 6C) (33).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [33] L. G. Davis, S. C. Willis, S. J. Macfarlan, Lithic technology, cultural transmission, and the nature of the Far Western Paleoarchaic/Paleoindian co-tradition, in Meeting at the Margins, D. Rhode, Ed. (Univ. Utah Press, 2012), pp. 47–64.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
Premisecitation
Clovis was dated to ~12.7 to ~13 ka ago and Folsom ~12.2 to ~12.7 ka ago.
“It was not until many years later that Clovis was dated to ~12.7 to ~13 ka ago and Folsom ~12.2 to ~12.7 ka ago (7).”
Quote in the paperNot a substantial claim0 of 1 sources checked
- cites [7] M. R. Waters, T. W. Stafford, The First Americans: A review of the evidence for the late-Pleistocene peopling of the Americas, in Paleoamerican Odyssey, K. E. Graf, C. V. Ketron, M. R. Waters, Eds. (Texas A&M Univ. Press, 2014), pp. 541–560.
  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

56 of 56

The paper relies on this without support.
The connection between the artifact assemblages of the ~14- to ~15-thousand-year-old North American sites and later Clovis and Western Stemmed Traditions remains unclear.
“The connection between the artifact assemblages of the ~14- to ~15-thousand-year-old North American sites and later Clovis and Western Stemmed Traditions remains unclear.”
The paper relies on this without support.
According to the geological principle of inclusions, any items, such as artifacts, in an undisturbed sedimentary deposit are at least as old as the sediments that contain them.
“according to the geological principle of inclusions, any items, such as artifacts, in an undisturbed sedimentary deposit, such as the floodplain clays at the Friedkin site, are at least as old as the sediments that contain them”
The authors state this as an assumption.
The U and Th decay series are in secular equilibrium in the dated sediments.
“The U and Th content of the sediments, assuming secular equilibrium in the decay series, 40K, and Rb, was determined by inductively coupled plasma mass spectrometry by ALS Laboratories (Reno, NV).”
The paper relies on this without support.
The moisture content of the dated sediments during burial was similar to that of the nearby pedons used to derive it.
“Moisture content (weight percent) during the burial period was derived from instrumented, nearby pedons whose floodplain soils were similar to those that formed along a higher-order tributary, such as Buttermilk Creek (11).”
The paper relies on this without support.
The cosmic ray dose rate component can be estimated from the current depth of burial.
“A significant cosmic ray component between 0.24 and 0.29 mGy/year was included in the estimated dose rate, taking into account the current depth of burial (44).”

5 of 5

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

Late Prehistoric/Late Archaic point totals disagree
Minor
The paper lists 10 Late Prehistoric and 35 Late Archaic diagnostic points, totaling 45. It later accounts for 44 in chronological order and four out of order, totaling 48.

1 of 1

Cosmic ray contributions to dose rates for luminescence and ESR dating: Large depths and long-term time variations
Prescott, J. R., & Hutton, J. T. (1994) · Radiation Measurements · doi:10.1016/1350-4487(94)90086-8 · Cited by 3,626
OPTICAL DATING OF SINGLE AND MULTIPLE GRAINS OF QUARTZ FROM JINMIUM ROCK SHELTER, NORTHERN AUSTRALIA: PART I, EXPERIMENTAL DESIGN AND STATISTICAL MODELS*
Galbraith, R. F., Roberts, R. G., Laslett, G. M., YOSHIDA, H., & Olley, J. M. (1999) · Archaeometry · doi:10.1111/j.1475-4754.1999.tb00987.x · Cited by 2,495
The single aliquot regenerative dose protocol: potential for improvements in reliability
Murray, A. S., & Wintle, A. G. (2003) · Radiation Measurements · doi:10.1016/s1350-4487(03)00053-2 · Cited by 1,983
A review of quartz optically stimulated luminescence characteristics and their relevance in single-aliquot regeneration dating protocols
WINTLE, A. G., & Murray, A. S. (2005) · Radiation Measurements · doi:10.1016/j.radmeas.2005.11.001 · Cited by 1,892
Deposition models for chronological records
Ramsey, C. B. (2008) · Quaternary Science Reviews · doi:10.1016/j.quascirev.2007.01.019 · Cited by 1,772
Advances in luminescence instrument systems
Bøtter-Jensen, L., Bulur, E., Duller, G. A. T., & Murray, A. S. (2000) · Radiation Measurements · doi:10.1016/s1350-4487(00)00039-1 · Cited by 764
Statistical aspects of equivalent dose and error calculation and display in OSL dating: An overview and some recommendations
Galbraith, R. F., & Roberts, R. G. (2012) · Quaternary Geochronology · doi:10.1016/j.quageo.2012.04.020 · Cited by 730
Monte Verde: Seaweed, Food, Medicine, and the Peopling of South America
Dillehay, T. D., Ramírez, C., Pino, M., Collins, M. B., Rossen, J., & Pino-Navarro, J. D. (2008) · Science · doi:10.1126/science.1156533 · Cited by 695
Estimating the component ages in a finite mixture
Galbraith, R. F., & Green, P. F. (1990) · International Journal of Radiation Applications and Instrumentation Part D Nuclear Tracks and Radiation Measurements · doi:10.1016/1359-0189(90)90035-v · Cited by 575
Optical dating of Holocene sediments from a variety of geomorphic settings using single grains of quartz
Olley, J. M., Pietsch, T., & Roberts, R. G. (2003) · Geomorphology · doi:10.1016/j.geomorph.2003.09.020 · Cited by 446
Terminal Pleistocene Alaskan genome reveals first founding population of Native Americans
Moreno-Mayar, J. V., Potter, B. A., Vinner, L., Steinrücken, M., Rasmussen, S., Terhorst, J., Kamm, J. A., Albrechtsen, A., Malaspinas, A.-S., Sikora, M., et al. (2018) · Nature · doi:10.1038/nature25173 · Cited by 316
DNA from Pre-Clovis Human Coprolites in Oregon, North America
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Halligan, J. J., Waters, M. R., Perrotti, A., Owens, I. J., Feinberg, J. M., Bourne, M. D., Fenerty, B., Winsborough, B., Carlson, D., Fisher, D. C., et al. (2016) · Science Advances · doi:10.1126/sciadv.1600375 · Cited by 259
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OSL ages of the Clovis, Late Paleoindian, and Archaic components at Area 15 of the Gault Site, Central Texas, U.S.A.
Rodrigues, K., Rink, W. J., Collins, M. B., Williams, T. J., Keen-Zebert, A., & Lόpez, G. I. (2016) · Journal of Archaeological Science: Reports · doi:10.1016/j.jasrep.2016.03.014 · Cited by 4

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Research works printed but not linked: 8

M. R. Waters T. W. Stafford The First Americans: A review of the evidence for the late-Pleistocene peopling of the Americas in Paleoamerican Odyssey K. E. Graf C. V. Ketron M. R. Waters Eds. (Texas A&M Univ. Press 2014) pp. 541–560.
M. R. Waters C. D. Pevny D. L. Carlson Clovis Lithic Technology: Investigation of a Stratified Workshop at the Gault Site Texas (Texas A&M Univ. Press 2011).
M. B. Collins Archeology in Central Texas in The Prehistory of Texas T. K. Perttula Ed. (Texas A&M Univ. Press 2004) pp. 101–126.
J. Lohse, S. L. Black, L. M. Cholak, Toward an improved Archaic radiocarbon chronology for Central Texas. Bull. Texas Archeol. Soc. 85, 259–287 (2014).
C. B. Bousman B. W. Baker and A. C. Kerr Paleoindian Archeology in Texas in The Prehistory of Texas T. K. Perttula Ed. (Texas A&M Univ. Press 2004) pp. 15–97.
N. Flegenheimer L. Miotti N. Mazzia Rethinking early objects and landscapes in the Southern Cone: Fishtail-point concentrations in the Pampas and northern Patagonia in Paleoamerican Odyssey K. E. Graf C. V. Ketron M. R. Waters Eds. (Texas A&M Univ. Press 2014) pp. 359–376.
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Preface to the Second Edition
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Index
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Preface to the First Edition
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Notes
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What Do You Do When No One’s Been There Before?
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Glaciers, Climates and Environments of Ice Age North America
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Who, from Where, When, and How?
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Ascertaining Archaeological Evidence of Antiquity
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Pre-Clovis projectile points in North America
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The Buttermilk Creek Complex and the origins of Clovis at the Debra L. Friedkin Site, Texas
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Pre-Clovis Lithic Technology at the Debra L. Friedkin Site, Texas: Comparisons to Clovis through Site-Level Behavior, Technological Trait-List, and Cladistic Analyses
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Dating of a large tool assemblage at the Cooper’s Ferry site (Idaho, USA) to ~15,785 cal yr B.P. extends the age of stemmed points in the Americas
Davis, L. G., Madsen, D. B., Sisson, D. A., Becerra‐Valdivia, L., Higham, T., Stueber, D. O., Bean, D. W., Nyers, A. J., Carroll, A., Ryder, C., et al. (2022) · Science Advances · doi:10.1126/sciadv.ade1248 · Cited by 36
Clovis, Folsom, and Midland components at the Debra L. Friedkin site, Texas: context, chronology, and assemblages
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Authors: Waters, M. R., Keene, J. L., Forman, S. L., Prewitt, E. R., Carlson, D. L., & Wiederhold, J. E.
Affiliations: Texas A&M University (US)
Baylor University (US)
The University of Texas at Austin (US)
Corresponding author: Waters, Michael R.
ORCID: Waters, Michael R.
Keene, Joshua L.
Forman, Steven L.
Carlson, David L.
Venue: Science Advances
Publisher: American Association for the Advancement of Science (AAAS)
Published: 2018-10-05
Volume: 4
Issue: 10
Pages: eaat4505-eaat4505
ISSN: 2375-2548 (ISSN-L)
DOI: 10.1126/sciadv.aat4505
PMC: PMC6200361
OpenAlex: W2898132821
Cited by: 115
References: 39
Citations by year: 2026: 3 · 2025: 11 · 2024: 3 · 2023: 10 · 2022: 19 · 2021: 40 · 2020: 13 · 2019: 14 · 2018: 2
FWCI: 47.68
Type: journal article
Language: en
Open access: gold
doi.org
Locations: Science Advances (publishedVersion)
Europe PMC (PubMed Central) (publishedVersion, cc-by-nc)
PubMed Central (publishedVersion, cc-by-nc)
PubMed (publishedVersion)
Funders: North Star Archaeological Research Program
Elfrieda Frank Foundation
Topics: Social Sciences › Anthropology › Pleistocene-Era Hominins and Archaeology
Social Sciences › Archeology › Archaeology and ancient environmental studies
Physical Sciences › Earth and Planetary Sciences › Atmospheric Science › Geology and Paleoclimatology Research
Keywords: pre-Clovis, projectile points, stemmed projectile points, Folsom points, peopling of the Americas, Late Pleistocene, lithic chronology, Texas
MeSH terms: Americas, Archaeology, Bayes Theorem, Geology, Humans, Luminescent Measurements, Texas, Geologic Sediments, History, Ancient, Human Migration

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Pre-Clovis projectile points at the Debra L. Friedkin site, Texas—Implications for the Late Pleistocene peopling of the Americas

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