“A Statistical Analysis of the Lithics from the Calico Site (SBCM 1500A), California”, Journal of Field Archaeology, Winter 1979

Posted on Tuesday, July 6th, 2010

This is a summary of Duvall and Venner’s publication – “A Statistical Analysis of the Lithics from the Calico Site (SBCM 1500A), California”, published in the Journal of Field Archaeology, 1979.

The Calico Early Man Site is a possible Paleo-Indians lithic workshop for stone tools and a simple quarry archaeological site in the Mojave Desert. It is located 16 miles (26 km) northeast of Barstow, California in the Calico Mountains foothills, in San Bernardino County, California.

The Calico Early Man Site has three components of differing ages:(1) artifacts of the Lake Manix Lithic Industry found on and just below the surface at elevations greater than 543 m (1,781 ft), the shoreline elevation of a 236 km2 (91 sq mi) freshwater Pleistocene lake which emptied approximately 18,000 years ago.
(2) artifacts of the Calico Lithic Industry, recovered from nested Pleistocene alluvial deposits stratigraphically beneath a 100,000 year old soil profile: the deposits dated to 135,000 years by thermoluminescence (TL) and about 200,000 years by uranium-series analysis.
(3) The Rock Wren Biface, a large well-formed biface tool recovered from a younger nested-inset alluvial deposit at Calico: dated by sediment thermoluminescence (sediment TL) to 14,400 ±2,200 years year ago. A test pit located near the discovery location is currently being excavated and is yielding putative artifactual material.
The stone tools of these industries, along with preforms, lithic core, technical flakes, and pieces of angular debitage, mainly of chalcedony, are found on and in late middle Pleistocene-age fanglomerates and younger inset alluvial terraces in the Calico Hills (also known as the Yermo Hills) east of the Calico Peaks and the Calico Mountains. The location is in the central portion of southern California’s Mojave Desert. Historically, this archaeological project has also been known as The Calico Mountains Archaeological Site and The Calico Hills Archaeological Site. Today, it is simply called The Calico Site.

Manix Basin
In most of the Great Basin region, Late Pleistocene and Holocene alluviation has effectively buried and sealed earlier Pleistocene sediments and possible evidence of pre-Clovis cultures. In the Manix Basin (Lower Mojave Valley) of San Bernardino County, California, however, a fortuitous ensemble of environmental factors relating to mountain building; climatically controlled conditions for lake formation, alluviation, and erosion; faulting and folding; and significant erosion of ancient lacustrine plain sediments by the modern drainage have rendered relatively accessible for archaeological investigation a series of deposits that represent more than 350,000 years of Quaternary history.

The Manix Basin, a structural basin in the central Mojave Desert, is the third and lowest major valley of the Mojave River, presently an exotic stream with episodic flow, which has its source in the San Bernardino Mountains, some 200 km (120 mi) to the southeast.

A freshwater lake developed in the basin about 400,000 – 500,000 years ago near to the Calico Archaeological Site. The lake was present until the late Pleistocene. The last high stand of Lake Manix was at 543 m (1,781 ft) and had a surface area of approximately 236 km2 (91 sq mi). This lake drained, probably catastrophically, approximately 18,100 years ago, probably as a result of a major increase in river inflow or tectonic movement on the Manix fault.[1]

The lacustrine, fluvial, and alluvial sediments of the Pleistocene Manix Formation contain remains of numerous Rancholabrean animals ranging in age from approximately 20,000 years to well in excess of 350,000 years before present.[1] Fossils recovered from the section include: camel, horse, mammoth, saber-tooth cat, dire wolf, short-faced bear, coyote, flamingo, pelican, eagle, swan, geese, mallard duck, ruddy duck, canvas backed duck, double-rested cormorant, grebe, crane, seagull and stork.[1]

 Prehistoric tools
Thousands of rocks that bear a strong resemblance to prehistoric tools have been found at the site, both on the surface, and up to 8 m (26 ft) below the surface. Scientifically dated to over 200,000 BP, the excavated subsurface objects are many times older than the traditional date of the first human entry into the Americas, approximately 11,000 BP.

The Debate —  The debate centers on whether the “tools” were made by humans (i.e., artifacts), or through typical geological processes (i.e. geofacts). The general scientific consensus is that the subsurface items are geofacts.[2]

 In addition to formed tools, more than 60,000 lithic flakes or technical flakes and pieces of angular debitage (flintknapping debris) have been recovered from Master Pits I and II at Calico. The number of formed stone tools now exceeds 8,000 (as analysis and cataloging efforts continue. Tools in the Calico lithic assemblage were fashioned on cores, flakes, and blades. Most were fashioned by simple hard hammer percussion flaking and flint knapping, some were made using ground or lap anvils, including by bipolar techniques.

 Artifacts or geofacts?
The artifactual character of the Calico lithic assemblage has been questioned (Haynes 1973; Payen 1982a, 1982b; Taylor and Payen 1979; Duvall and Venner 1979). Haynes (1973) postulated that rock fracturing by tectonic stresses, weather, rock-on-rock percussion in streams and mudflows, pressure retouch of buried cobbles, and successive generations of flake removal and separation from cores through cycles of erosion and redeposition could have occurred during deposition of the alluvial deposits at Calico and produced specimens indistinguishable from artifacts.

However, such mechanisms do not frequently cause artifact-like fracturing. This is especially true with regard to the small, delicate flaking seen on light-duty tools such as burins, gravers, becs, denticulates, and reamers. Studies indicate that stream transport abrades and rounds rocks quickly; it does not dislodge artifact-like flakes by percussion. Streams are capable of generating only about 10 percent of the force needed to dislodge significant numbers of percussion flakes; forces in mudflows are lower due to viscosity. If streams produced pseudo-artifacts, dry streambeds would be littered with such specimens. They are not. The only contexts known to produce significant amounts of percussive flaking (and occasional pseudo-artifacts) are high-energy storm conditions on rocky beaches and certain types of rock falls (landslides and waterfalls).

Flake scar angles – Past Research
Payen (1982) studied flake scar angles as traits for distinguishing artifacts from geofacts. He tested a method developed by Barnes (1939) who had compared frequency of obtuse angles on eoliths, natural fractures, and artifacts. Barnes found obtuse angles on 72% of eoliths, 75% of natural fractures, and 18% of artifacts and concluded that “The flaked tools of an industry…may be considered to be of human origin if not more than 25% of the angles scar-platform are obtuse (90 degrees and over)” (Barnes 1939:111). Payen measured all flake angles on each Calico specimen in his sample. It is conceivable that flake scars were confused for striking platforms. Flaking from one side of a specimen can often remove earlier platform areas on the other side. Angles between two flake scars are different from angles between platforms and derivative flake scars.

Payen compared mean angle values for Calico specimens with those on specimens selected as representing controlled and uncontrolled fracture. He found that “Statistically, there is no significant difference between the sample of alleged tools and the uncontrolled fracture series.” (Payen 1982:200). Payen’s conclusion, however, does not follow unambiguously from his data. Neither Payen, nor Barnes, has established a single trait criterion for distinguishing artifacts from geofacts.[citation needed]

Duvall and Venner (1979:462) examined a sample of Calico artifacts and concluded they were form-selected examples of naturally flaked rocks. This assessment was based on variances in seven attributes (length, width, thickness, flake angle, medial axis angle lateral edge angle, and distal edge angle) and comparison with comparable attributes on specimens in eight Paleoindian collections reported by Wilmsen (1970). Wilmsen was concerned with differences in tool technologies and functions, not with distinguishing artifacts from geofacts.

Duvall and Venner demonstrated that the statistical techniques used in their testing bears on the question of the artifactuality of the Cakico specimens. They illustrate that the examined Calico tools are not from the same population as the non-bifacial tools and utilized flakes from certain Paleoindian sites. However, the Calico Lithic Industry is a morphological parallel of (and time-equivalent to) Old World Paleolithic industries, not to much more recent PaleoIndian industries.

Both the Duvall and Venner, and the Payen papers have been criticized by those supporting the pro-artifact argument.[3] However, the present consensus, as demonstrated by Duvall and Venner, is that there is no evidence of human activity at the Calico Early Man site. This consensus was developed based on a number of factors, including: The lack of other evidence of human activity (e.g. human or animal remains, or non-tool artifacts).
The deep antiquity of the site (the next oldest date for human artifacts in the Americas is 30,000 BP, and that date itself is controversial).
The sheer number of possible tools, up to 60,000 by one account.[4]
The research by Duvall and Venner, Payen, and others provided possible natural explanations for the stone objects.

 History of excavations at the Calico Early Man Site — Visitor center, June 2010In 1959 Louis Leakey, while at the British Museum of Natural History in London, received a visit from Ruth DeEtte Simpson, an archaeologist from California. Simpson had acquired what looked like ancient scrapers from a site in the Calico Hills and showed it to Leakey.

Leakey viewed it as important to study the Calico Hill site,[5] as he was convinced that the number and distribution of native languages in the Americas required more time than 12,000 years to evolve and acquire their current distribution.[6] The opportunity to test this theory came four years later in 1963, when Leakey obtained funds from the National Geographic Society and commenced archaeological excavations with Simpson. Mary Leakey did not share his visionary views.[5] However,Louis Leakey continued to visit the site several times a year and was connected with the project until his death in 1972. The site was taken over by California’s Bureau of Land Management and was opened to the public. It presently offers a visitor center, gift shop, and guided walking tour.

1.^ a b c http://www.calicodig.org/text?page=4 Calico Early Man Site: The Setting]
2.^ See Haynes, as one example. Published studies in peer-reviewed journals consistently support the “geofact” explanation.
3.^ Patterson, et al.
4.^ AmericanWest’s Calico Site Update
5.^ a b Morell, pp. 266-267.
6.^ Calico Site Update.
Bischoff, J.L., R.J. Shlemon, T.L. Ku, R.D. Simpson, R.J. Rosenbauer, & F.E. Budinger, Jr., “1981 Uranium-series and Soils-geomorphic Dating of the Calico Archaeological Site, California”, Geology V9 (12), pp. 576-582.
Budinger Jr., Fred E., Oberlander, Theodore Calicodig.com “This web site describes and analyzes the Calico Archaeological Site and the Calico Lithic Industry”. With many stone object photos.
Debenham, N., (1998) Thermoluminescence Dating of Sediment from the Calico Site (California) (CAL1), Quaternary TL Surveys, Nottingham, United Kingdom, 1998.
Duvall, James G., and Venner, William Thomas, “A Statistical Analysis of the Lithics from the Calico Site (SBCM 1500A), California”, Journal of Field Archaeology, Winter 1979: Vol. 6, No. 4, pp. 455-462.
Haynes, Vance (1973) “The Calico Site: Artifacts or Geofacts?”, Science, vol. 181, no. 4097, July 27, 1973, pp. 305-310.
Morell, Virginia (1995) Ancestral Passions: The Leakey Family and the Quest for Humankind’s Beginnings, Simon & Schuster, pp. 266-267.
Payen, L., “Artifacts or geofacts at Calico: Application of the Barnes test,” in Peopling of the New World, Ericson J., Taylor, R., and Berger, R., eds. Los Altos, California: Ballena Press, 1982, pp. 193–201.
Patterson, Leland W.; Hoffman, Louis V.; Higginbotham, Rose Marie; Simpson, Ruth D. (1987) “Analysis of Lithic Flakes at the Calico Site, California”, in Journal of Field Archaeology, Vol. 14, No. 1 (Spring, 1987), pp. 91-106.
AmericanWest’s North American Archaeology Section, Calico Site Update. “. . .over 60,000 tools and flakes have been collected”.
Friends of Calico Early Man Site; 2024 Orange Tree Lane, Redlands, CA 93474

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