jfa(1983)criteria for determining the attributes of man made lithics_patterson.pdf

Criteria for Determining the Attributes of Man-Made LithicsAuthor(s): Leland W. PattersonSource: Journal of Field Archaeology, Vol. 10, No. 3 (Autumn, 1983), pp. 297-307Published by: Boston UniversityStable URL: http://www.jstor.org/stable/529545Accessed: 02/07/2010 12:30

Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available athttp://dv1litvip.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unlessyou have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and youmay use content in the JSTOR archive only for your personal, non-commercial use.

Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained athttp://www.jstor.org/action/showPublisher?publisherCode=boston.

Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printedpage of such transmission.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

Boston University is collaborating with JSTOR to digitize, preserve and extend access to Journal of FieldArchaeology.

http://dv1litvip.jstor.org

http://www.jstor.org/stable/529545?origin=JSTOR-pdf

http://dv1litvip.jstor.org/page/info/about/policies/terms.jsp

http://www.jstor.org/action/showPublisher?publisherCode=boston

Introduction

In the last 30 years, several investigations have been published on archeological sites in the New World that are supposed to have been occupied by humans at a very early date. Some of these sites are Calico, 1 Texas Street,2 Pikimachay Cave,3 Sheguiandah,4 Valsequillo Region sites,5 Taber,6 the Sierra Pinacate,7 and Yuha Pinto Wash.8 H. L. Minshall9 and G. F. Carterl° have published general reviews on this subject. Publications on early-man sites in the New World generally receive much

1. W. C. Schuiling, ed., "Pleistocene Man at Calico," Quarterly of San Bernardino County Museum Association 26:4 (1979) 1 - 112.

2. G. F. Carter, Pleistocene Man at San Diego (Baltimore 1957).

3. R. S. MacNeish, "The Early Man Remains from Pikimachay Cave, Ayacucho Basin, Highland Peru," in R. L. Humphrey and D. Stan- ford, eds., Pre-Llano Cultures of the Americas: Paradoxes and Pos- sibilities (Anthropological Society of Washington:1979) 1-47.

4. T. E. Lee, "The Antiquity of the Sheguiandah Site," The Cana- dian Field-Naturalist 71 (1957) 117- 135.

5. C. Irwin-Williams, "Summary of Archaeological Evidence from the Valsequillo Region, Puebla, Mexico," in D. L. Browman, ed., Cultural Continuity in Mesoamerica (The Hague 1978) 7-22.

6. A. M. Stalker, "Indications of Wisconsin and Earlier Man from the Southwest Canadian Prairies," Annals of the New York Academy of Sciences 288 (1977) 119-136.

7. J. D. Hayden. "Pre-Altithermal Archaeology in the Sierra Pina- cate, Sonora, Mexico, " AmAnt 41 (1976) 274-289.

8. W. M. Childers and H. L. Minshall, "Evidence of Early Man Exposed at Yuha Pinto Wash," AmAnt 45 (1980) 297-308.

9. H. L. Minshall, The Broken Stones (LaJolla, California 1976).

10. G. F. Carter, Earlier Than You Think (College Station, Texas 1980).

criticism. As R. S. MacNeishl1 observes, however, "The proof will not go away, so we had better learn to live with it and start attempting to interpret the evidence in some sort of rational manner, rather than trying to ignore or ridicule it out of existence."

One type of criticism given for very early man sites in the New World is that lithic specimens are not really man-made, such as by Haynes12 for the Calico site. The author13 has previously commented on the need to use objective criteria for determining if lithic collections that appear "primitive" are man-made or are instead the fortuitous products of nature. This article discusses a number of attributes that are of value in demonstrating the man-made nature of lithic specimens.

One of the reasons that lithic collections of very early man are generally criticized on a subjective basis is that relatively few archeologists in the United States have received good training in lithic technology.14 Another reason is that experimental flintknapping has not been applied often to the analysis of actual archeological materials.15 Despite the large number of years of study of

11. MacNeish, op. cit. (in note 3) 47.

12. C. V. Haynes, "The Calico Site: Artifacts or Geofacts?," Sci- ence 181 (1973) 305-310.

13. L. W. Patterson, "Comments on Texas Street Lithic Artifacts," Anthropological Journal of Canada 15 (1977) 15-25; L. W . Patter- son, ''Comments on a Statistical Analysis of Lithics from Calico," JFA 7 (1980) 374-377, in reference to James G. Duvall and William T. Venner, "A Statistical Analysis of the Lithics from the Calico Site (SBCM l500A), California," JFA 6 (1979) 455-462.

14. L. W. Patterson, "Instruction in Lithic Technology in U.S. Uni- versities, " North American Archaeologist 2 (1980) 19-24.

15. L. 87. Patterson, ''Goals of Experimental Flintknapping," Flint-

Criteria for Determining the Attributes of Man-Made Lithics

Leland W. Patterson Houston, Texas

This article oJfers a discussion of the criteria for lithic attributes that distinguish between man-made and naturally fractured stone objects. Emphasis is placed on the consistent patterns of attributes characteristic of lithic manufacturing by man. This subject is especially important at the present timew because of the increasing number of very early dates proposed for human occupation of sites in the New World. It is urged that this type of study be made in an objective mannerw as opposed to the many subjective comments given on this subject in the past.

298 Criteria for Determining the Attributes of Man-Made LithicslPatterson

lithic artifacts from archeological sites, lithic technology is still not a mature field. There does seem to be a greater present interest in lithic technology, which probably indicates more future progress.

The author has previously urged that study of lithic collections proposed to have been created by very early man in the New World be done on an explicit, objective basis, rather than conducting subjective voting contests by investigators.16 Even the personal opinion of a lithic expert is of little value if explicit technological reasons cannot be given to explain an opinion, either positive or negative. For example, MacNeish states that several lithic experts had no doubts that the earliest specimens (Pa- caicasa phase) at Pikimachay Cave were all tools, instead of naturally formed objects.17 This type of statement means little without a rigorous technical discussion of significant lithic attributes. The published reports to date on proposed sites in the New World occupied by very early man generally fall short of complete technological explanation. The body of published criticism on these sites is not any better, consisting mainly of completely subjective opinions. As will be discussed here, even natural damage to flake edges can be discussed in explicit terms, instead of subjectively saying "I see no pattern."

The comments by Haynes18 on the Calico site lithic collection are a good example of subjective comments, without consideration of specific lithic attributes that could distinguish man-made manufacturing patterns. A list is given of ways that stone could fracture from natural causes, and then an opinion is given that the Calico lithics are a result of natural fractures, without presenting any detailed specific qualitative and quantitative studies of the attributes of the lithic materials in question. This type of subjective discussion should be avoided, as it unduly influences general opinion without any real basis.

There is little in the current literature to aid the analyst in distinguishing man-made lithic attributes. Oakley's19 short discussion on this subject is a principal reference. Carter20 has also written on this type of problem. It is hoped that the present article will aid the lithic analyst in taking a more objective approach, by the consideration of specific lithic attributes related to patterns of man- made manufacture. If accepted methods of analysis can

knappers' Exchange 2:2 (1979) 7-8.

16. Patterson, op. cit. (in note 13) 24. 17. MacNeish, op. cit. (in note 3) 41.

18. Haynes, loc. cit. (in note 12).

19. K. P. Oakley, Man the Tool-maker (Chicago 1972) S-12. 20. Carter, op. cit. (in note 10) Chapter 4.

be evolved, this subject can be handled in a much more rational manner than has been done in the past.

Lithic Manufacturing Patterns

Since the forces of nature act in a random manner, naturally fractured lithic materials will usually occur in random patterns. In demonstrating the man-made nature of lithic collections, it is important to show consistent manufacturing patterns for products and debitage. Even if nature can produce lithic objects resembling simple man-made items, nature is not likely to do this often. Therefore, the frequency of occurrence at a given location of specimens with similar morphologies is important in demonstrating probable manufacturing patterns. Pro- duction of numerous lithic speci-mens with consistent morphology is certainly not a habit of nature. Quanti- tative data on amounts of each specimen type should therefore always be presented.

Comments here on consistent fracture patterns apply mainly to minerals without natural cleavage planes. In some cases, specimens of minerals having natural cleavage planes can appear to be the result of a manufacturing pattern. Fortunately, most lithic materials found on archeological sites, such as flint and basalt, do not have natural cleavage planes.

A frequent criticism of lithic collections from proposed sites of very early man is that samples are biased because only specimens that look man-made have been selected from all of the broken rock available. This criticism is based on the assumption that if nature breaks enough rock, significant amounts of specimens resembling man-made objects can be produced. This is an unconfirmed assumption. When faced with a large lithic collection, the only practical initial screening procedure is to select all of the specimens that look man-made. The investigator is then required to demonstrate by suitable criteria that the selected collection really is man-made. There are many good criteria available to make this demonstration.

A common comment made is that more studies should be made on the attributes of rock fractures from natural causes. The author is in ageement with this. There are, however, limitations on how widely natural fracturing can be studied, considering the limited resources of archeology. Someone can always propose more scenarios in which nature might fracture stone in ways to simulate man-made flaking. What is proposed here is a practical method to approach the problem of identifying primitive man-made assemblages when critics feel that the assemblages could have been produced by natural means. The steps to this approach are as follows.

1. Identify all typical man-made lithic attributes that nature is least likely to simulate often. This identification

Journal of Field ArchaeologylVol. 10, 1983 299

energy, ocean-beach storm conditions.26 In contratst, the mud and water flow conditions that form an alluvial fan, such as at the Calico Site,27 would be expected to break rock mainly by pressure, as viscous liquids and slurries inhibit high-velocity percussive interactions of rocks. Pressure fracturing gives different lithic attributes than the percussive-type flaking used by early man, as will be discussed further here.

Another condition in which nature can break rock is when flint nodules are held in a secure limestone matrix and there is a shift in the mass. Here, it is common to see shear fractures that have none of the key attributes of percussive fracture patterns.

Attributes of Lithic Flakes

1. Fracture Attributes

There are no demonstrated examples now available where nature has produced concentrations of percussion flakes of significant sizes, but there are many examples where nature has produced stone flakes by pressure fracturing and expansion of ice inclusions. In contrast, evidence shows that the production of large flakes by early man was done by the application of percussive force. In identifying lithic manufacturing activities of early man, it therefore becomes important to identify percussion- type fractures; this identification can best be done by the examination of attributes of lithic flakes. Attributes of flake scars on residual cores are difficult to examine. For example, in experimental percussion flaking, force bulbs are generally easy to see on most flakes produced, but the negative impressions of force bulbs in flake scars on cores are often difficult to observe. Various attributes of lithic flakes are illustrated in Figure 1.

26. Ibid. 11; Carter, op. cit. (in note 10) 105.

27. T. Clements, "The Geology of the Yermo Fan," in Schuiling, ed., op. cit. (innote 1)21-28.

can be done by experimental flintknapping and study of basic physical principles.

2. Analyze the lithic collection in question for all key attributes proposed.

3. Identify all key attributes that are present in quan- titatively significant amounts.

4. Demonstrate the likelihood of human manufacture by combinations of key attributes. Studies of single attributes will always remain unconvincing.

Spatial Considerations

When man manufactures lithic objects, the resulting debitage is normally confined to concentrations in small areas. There can, of course, be multiple concentrated areas. In contrast, nature produces fractured rock randomly dispersed, as Carter has observed for a variety of field conditions.21 Even if nature would leave concentrated areas of broken rock, the materials would not likely show a high frequency of typical man-made attributes. Therefore, concentrations of specimens showing typical man-made attributes in small spatial areas are important demonstrations of likely human activity. It is interesting to note that the Texas Street Site22 and the Calico Site23 both have concentrated areas of fractured rock having the typical attributes of man-made debitage. Concentra- tions of man-made debitage are easily explained. The knapper will normally remain in a single location while working on one or more products. M. H. Newcomer and G. de G. Sieveking have discussed how flake scatter- patterns are developed by the actions of individual flintknappers .24

Geological Considerations

Oakley25 states that "Nevertheless, under exceptional conditions naturally flaked stones occur which, if seen out of geological context, might be mistaken for artifacts." Thus, the geological context of a lithic collection becomes important in determining if nature would have had the probable capability of fracturing rock, especially in a percussive manner. The only published manner that nature can do much percussive fracturing is under high-

2 1. Ibid. 103- 111.

22. Patterson, op. cit. (in note 13) 17.

23. R. D. Simpson, L. W. Patterson, and C. A. Singer, "Early Lithic Technology of the Calico Site, Southern California," presented at the 10th Congress of International Union of Prehistoric and Protohistoric Sciences, Mexico City, 1981.

24. M. H. Newcomer and G. de G. Sieveking, "Experimental Flake Scatter-Patterns: A New Interpretive Technique," JFA 7 (1980) 345- 352.

25. Oakley, op. cit. (in note 19) 12.

RESIDUAL

/ STRIKING

LIP PLATFORM

/ ri / < STHIKING

FORCE PLATFORM

BULB ANGLE

THICKNESS

DISTAL

END

EDGE YIEW

/ \ ERAILLURE

/ 0 C SCARS

z - FORCE

{ \ BULB -\

\ RIPPLE

LINES

YENTRAL FAC

E

DORSAL FAC E

Figure 1. Attributes of lithic flakes.


It has been experimentally demonstrated that flakes produced by percussion have high percentages of prominent force bulbs on ventral faces adjacent to points of the application of force,28 and that flakes produced by pressure usually do not have significant force bulbs.29 The presence of distinct force bulbs is the key attribute in identifying percussion fractures.

Undulating ripple lines on the ventral faces of flakes are usually associated with percussion flaking. This condition can be quite variable, however, depending on the type of material being flaked. Significant ripple lines have occurred most often from fracture of fine-grained siliceous minerals, in experiments by the author. Ripple lines can also be formed during fracture from pressure, as can be demonstrated experimentally in fluting Folsom point replicates by use of lever-pressure devices.30 When npple lines occur during pressure flaking, they are usually rather fine compared to the coarse, prominent ripple lines resulting from percussion flaking of similar materials.

Small flake scars on force bulbs (errailures) are another atmbute of fractures caused by percussion. This attribute has not been observed often by the author on products from pressure-flaking experiments. Since percussion flaking is the most likely technique to have been used by early man, collections of proposed man-made flakes should have high percentages of force bulbs, bulb scars, and prominent ripple lines. This especially applies to flakes above 18 mm. square, which are not likely to have been produced by pressure flaking by man. Patter- son and Sollberger31 have noted that conventional pressure flaking does not usually produce significant quantities of flakes above 18 mm. square. In contrast, nature prob-

-

ably breaks more rock by pressure than by percussion, as natural situations involving percussive flaking are difficult to find. In fact, it is doubtful that very early man could produce large flakes by pressure, because no de- vice was available capable of producing very large pressure forces. Therefore, if collections of large-size lithic flakes display few force bulbs and prominent ripple lines on their ventral faces, there is a good possibility that these flakes may have been produced by natural forces.

28. J. B. Sollberger and L. W. Patterson, ''Prismatic Blade Repli- cation," AmAnt 41 (1976) table 3.

29. J. B. Sollberger and L. W. Patterson, "Attributes of Experimen- tal Folsom Points and Channel Flakes," Bulletin of Texas Archeolog- ical Society 51 (1980) table 4; L. W. Patterson and J. B. Sollberger, "Replication and Classification of Small Size Lithic Debitage," PAnt 23 (1978) 103-112.

30. Sollberger and Patterson, loc. cit. (in note 28).

31. Patterson and Sollberger, loc. cit. (in note 28).

Oakley32 and Carter33 have noted ocean beach conditions where nature does percussive flaking, but Oakley also notes: 4'But usually the flakes produced in such ways show flatter and more diffuse bulbs of percussion than those produced by purposeful blows." This fact can be explained in physical terms. In nature, the object being flaked by percussion is not held tightly and is free to move. When a core moves very much during force application, energy transfer from applied force is less ef- ficient. Flake removals under this condition will tend to show less concentrated patterns of force application. The opposite applies to flaking by man, where the core is usually held in a fairly fixed position and subjected to rapid concentrated percussive blows. The high velocity of percussive blows by man probably also tends to give clearer attributes of flake fracture than when nature per- forms percussive flaking under unusual conditions.

It is more difficult to observe fracture attributes on coarse-grained minerals such as porphyry and quartzite. Fine-grained minerals such as flint and obsidian tend to show fracture attributes very clearly, while coarse-grained minerals require more careful magnified observation. Childers34 notes that some crude prismatic flakes can be produced experimentally from coarse-grained stone without bulbs of force.

As Oakley3s notes, it is normally easy to distinguish thermal fractures of lithic materials. Striking platforms, force bulbs, and corresponding ripple lines will be ab- sent, and ventral faces of flakes will often have coarse appearances. Many thermal fractures will be of the pot- lid type.

Another indication of percussive flaking is crushing of striking platforms. This can take the form of complete or partial crushing of the residual striking platform on a flake, or the crushing down of the dorsal face from the striking platform. Crushing is fairly easy to distinguish under magnification, as it results in ragged, irregular flake scars and many flake scar terminations will be stepped. Force application by pressure can also remove residual striking platforms from flakes, but here fracture scars will usually not have many step terminations.

It is common to hear people say that they may have seen examples of natural percussion flaking. These state- ments are seldom definitive. Many of the examples of percussion flaking that are seen "in nature" are possibly man-made. It was common for Indians to do widespread

32. Oakley, op. cit. (in note 19) 11.

33. Carter, op. cit. (in note 10) 105.

34. W. M. Childers, "Ridge-Back Tools of the Colorado Desert," AmAnt 42 (1977) 242-248.

35. Oakley, op. cit. (in note 19) 1 1.


testing of lithic raw materials, and examples of man- made percussion flaking are possible in most recent geological contexts where suitable stone sources occur. For example, many stream beds in Texas with chert cobbles have widely dispersed examples of man-made percussion flaking, not associated with concentrated lithic procure- ment activities.

2. Striking Platform Angle Controlled production of stone flakes normally re-

quires a fairly flat striking- platform to act as a force application point. In addition, it is well known to experimental flintknappers that controlled flaking cannot be done with striking platform angles greater than 90°. An obtuse striking platform angle directs force into the mass of the core, so that no oblique force can be applied to generate an outward tensile force element necessary for controlled flake removal. Stone can be fractured with an obtuse striking platform angle, but not in a manner to obtain controlled flaking. The striking platform angle is defined as the angle between the surface of the striking platform and the adjacent face of the core from which a flake will be removed. On a flake, the angle of the striking platform is the angle between the residual surface of the striking platform and the dorsal surface, as shown in Figure 1.

The flintknapper can vary the angle of the striking platform as one of the independent variables used to control lengths of the product flakes but this angle must always be less than 90°. In an example of experimental manufacture of prismatic blades, Sollberger and Patterson36 have shown striking platform angles varying from 60° to 90°, with 75° being a typical average. It should be noted that if nature simulates man-made controlled flaking, striking platform angles will be less than 90° as in man-made examples.

In a study by A. S. Barnes,37 edge angles on stone tools and naturally fractured stone were measured. This is equivalent to measuring the striking platform angle on a core after flake removal. E. N. Wilmsen38 has used the equivalent '4beta" angle on a flake, which is the angle from the plane of the striking platform down to the ventral surface of the flake. In controlled flaking, the "beta" angle will be consistently acute, but it should be noted that the "beta" angle is a dependent product variable, while the striking platform angle is an inde-

36. Sollberger and Patterson, loc. cit. (in note 27).

37. A. S. Barnes, '4The Differences Between Natural and Human Flaking on Prehistoric Flint Implements," AmAnth 41 (1939) 99-1 12.

38. E. N. Wilmsen, Lithic Anfllysis and Cultural Interffierence: A Pa- leo-Indian Case (Tucson 1970).

pendent variable that can be controlled by the flintknapper. For general lithic analysis, the striking platform angle is a better attribute to use than the "beta" angle, since the striking platform angle is an independent variable, and because prominent bulbs of force on ventral surfaces of flakes can frequently interfere with "beta" angle mea- surements.

In the study by Barnes,39 flake-scar edge angles were found to be generally less than 90° in collections of man- made tools, and the author is in agreement with this. In collections both of man-made and naturally fractured stone, however, Barnes identified many specimens with flake-scar edge angles greater than 90°. These observations must result either from incorrect identification of striking platform geometry or from incorrect angle mea- surements, if man-made controlled flaking or simulated controlled flaking by nature is being identified. Core flake-scar edge angles, and corresponding "beta" angles on product flakes, cannot be obtuse in controlled flaking, for the same general reasons that the angles of striking platforms cannot be obtuse in controlled flaking. On a flake, the striking platform and "beta" angles are most often incorrectly identified when a secondary fracture has removed the true residual surface of the striking platform and has left another flake-scar surface which gives the incorrect impression that these angles are obtuse. It must be emphasized that intact examples of controlled flaking will have striking platform and "beta" angles under 90°. Studies using averages of acute and obtuse angles have little meaning, since unlike attributes are being averaged together.40 The significance of the striking platform angle is widely misunderstood in relation to identifying man-made flakes. Controlled flaking by man will consistently produce flakes with striking platform angles of less than 90°, but this attribute is not definitive of man-made flaking by itself, as nature can also produce flakes with acute striking platform angles. Studies such as that published by R. E. Taylor and L. A. Payen41 that use "beta" angles on flakes as the basis for concluding that the sites of Calico and Texas Street do not have man-made specimens are questionable for reasons given here.

Previous investigators have obtained the impression that collections of naturally produced lithic flakes have

39. Barnes, loc. cit. (in note 36) 109.

40. L. W. Patterson, "The Analysis of Striking Platform Geometry," Flintknappers' Exchange 4 ( 1981 ) 18-20.

41. R. E. Taylor and L. A. Payen, "The Role of Archaeometry in American Archaeology: Approaches to the Evaluation of the Antiquity of Homo Sapiens in California," in Advances in Archaeological Method and Theory, Vol. 2, ed. Michael Schiffer (Academic Press: New York 1979) 239-283.


many striking platforms with obtuse angles, but this appears to be mainly a case of incorrect identification of striking platform geometry. For example, even when re- moving initial flakes from rounded stream cobbles, striking platforms with obtuse angles are not being used in controlled flaking. In this case, the angle of the striking platform appears to be obtuse because of the rounded edge. The actual geometry conforms to a core with a striking platform having an acute angle, except that the edge is rounded.

Collections of naturally fractured rock often superficially appear to have high percentages of flakes with striking platforms that have obtuse angles simply because so many residual striking platforms are missing, and secondary fracture planes are incorrectly identified as remnant striking platforms. Natural fracturing and un- directed fracturing by man-made causes, such as gravel crushing, produces fewer flakes with intact residual striking platforms, possibly because the random forces would seldom be directed exactly into the core being flaked, as would be done in man-made flaking. Also, both nature and mechanical gravel crushing are capable of generating very high pressure levels, which would tend to induce more secondary fractures to remove residual striking platforms from flakes.

3. Preparation of the Striking PlaMorm If a satisfactory striking platform does not exist on a

core being worked, the knapper will prepare one in order to create a suitable striking surface and to obtain a de- sired striking platform angle. As mentioned, the striking platform angle must be less than 90°, but can be varied to control flake length. Prepared striking platforms can be singly or multiply faceted, and a key point is that there is generally little remaining cortex. A multiply faceted striking platform can sometimes indicate that the striking platform angle is being controlled.

While man will sometimes use natural striking platforms covered with cortex, nature is more likely to do so on a consistent basis, because nature is likely to remove isolated flakes from the outside surfaces of undis- turbed raw material pieces. Evidence of the preparation of a striking platform is there.fore a key indication of manufacturing by man.

If a skilled knapper is involved, there may also be some evidence of the preparation of the edge of the striking platform. That is, striking platform overhangs are removed to eliminate concavities on adjacent core faces, thereby producing a series of short flake scars on the dorsal face of a flake adjacent to the proximal end at the striking platform. Edge grinding is sometimes also used to obtain more uniform edges of a striking platform, but this would not be expected in many early lithic indus-

tries, as it is generally a more refined technique used in the production of fine bifaces and prismatic blades.

4. Attributes of the Dorsal Face

Because of the random nature of natural forces, nature is not likely to remove many flakes in series on a single core. In contrast, knapping by man is likely to remove several flakes from a core, with selective use of striking platforms. Removal of several flakes from a core face will produce certain attributes on the dorsal faces of flakes. A high percentage of man-made flakes will have only partial or no remaining cortex on dorsal surfaces. Man-made flakes are more likely to have multiple flake scars on dorsal faces, indicating prior flake removals from the core. In addition, man-made flakes should have all flake scars on the dorsal face of the same apparent age, with no uneven surface weathering of separate flake scars. This circumstance results because man will generally remove all flakes from a core in a relatively short time period, while nature might randomly remove flakes from the same core over a long time period.

Prismatic blades with dorsal ridges parallel to the lat- eral edges and high length-to-width ratios (at least over 2) can be especially diagnostic, no matter how thick and crude, but only if present in significant percentages of a total flake collection. Prismatic blades can be produced fortuitously in small percentages.42 Large percentages of prismatic blades indicate that the special technique of selectively applying force above ridges on core faces was being used purposefully. The random forces of nature are not likely to be applied in this manner on a frequent selective basis. Repeated use of a single platform in experiments will often produce miscellaneous types of prismatic flakes.

5. Distribution of Flake Sizes

Certain types of lithic manufacturing activities will generate flakes that have distinctive, non-random, size- distribution patterns. For example, systematic bifacial reduction gives flake-size distributions of an exponential shape, skewed toward higher percentages of smaller size flakes.43 Patterns of this sort are not likely to occur in nature, and serve as another indication of lithic manufacturing activity by man. In a similar manner, purposeful manufacture of prismatic blades will sometimes give distinctive width-distribution patterns.44

As an example of the usefulness of patterns of flake- size distribution it can be experimentally demonstrated from a collection of flakes from the production of bifa-

42. Patterson and Sollberger, op. cit. (in note 28) 110

43. Patterson and Sollberger, op. cit. (in note 28) 111.

44 Sollberger and Patterson, op. cit. (in note 36) table 2.


cial handaxes that bifacial reduction was being done even without the presence of bifacial products.

Unifacial Edge Retouch Unifacially retouched stone tools are generally an im-

portant class of tools on archeological sites, and com- prise a major portion of lithic artifacts on early man sites. This group can include well-known types of stone tools such as gravers, perforators, scrapers, notched tools, and some types of knives, choppers, and denticulates. Com- pletely unifacial tool shapes would be one of the most difficult items for nature to reproduce by random forces. It would be difficult for random natural forces unidirec- tionally to fracture flake edges only on one face. It would be even more difficult for fortuitous forces to create the long, uniform, parallel flake scars characteristic of purposefully made unifacial tools, as shown by the experimental scraper replicate in Figure 2. It follows, then, that it would be extremely difficult to conceive of nature fortuitously creating an entire group of various well-made unifacial tools, with multiple examples of each tool type, that is the usual demonstration of a kit of man-made stone tools.

Nature and the fortuitous actions of hooved animals and man can cause edge damage on lithic flakes.45 The author's experience is that natural and fortuitous edge damage mostly consists of short, steep, uneven facets, that usually occur in a random bifacial manner. Figure 3 illustrates a typical example of a flake that has damage to its edge as a result of natural causes in a seasonally active stream bed. Fractures occur randomly in a bifacial

45. Robert J. MalloufS "An Analysis of Plow-Damaged Chert Arti- facts: the Brookeen Creek Cache(41HI86), Hill County, Texas,s' JFA 9 (1982) 79-98; Robert Miller, "Pseudo-Tools Created by Livestock from Halawa, Syria,s' JFA 9 (1982) 281-283.

Figure 3. Example of natural edge damage. Ca. 6 x magnification.

manner. The facets are short, uneven, and steeply transverse across the flake edge. It would be difficult to vis- ualize how random applications of force could create uniform, unidirectional retouch along a significant length of a flake edge. Fortuitous, unifacial damage to an edge generally has no uniform pattern of retouch.

It is common in experimental flintknapping for some flakes to be produced fortuitously that superficially resemble gravers, perforators, and notched tools. When the apparent working edges are examined, however, there is no series of uniform retouch present to form the observed shapes, and the geometry is entirely accidental. Any experienced lithic analyst with a 10-power magnifier can distinguish fortuitously shaped flakes from unifacial tools. Yet, the author has seen experienced archeologists argue for long time periods about a poten- tial stone tool, simply because not one of them had the sense to make a detailed observation with a magnifier. I suspect that many of the so-called "lithic experts" who show up to examine collections from sites supposed to have been occupied by humans at a very early time make only superficial observations of lithic attributes. As an example of superficial observation, the author has received comments that the edge damage on natural flakes illustrated by Oakley46 resembles retouch patterns of unifacial tools A careful examination of Oakley's illustrations shows that the flake scars do not form a uniform pattern as is characteristic of the results of perpendicular force applications in making unifacial tools. In Oakley's illustrations, flake scars at the edge go in a variety of angles from the plane of the ventral face of the specimens, instead of being parallel flake scars mainly perpendicular to the plane of the ventral face. Flake scars also vary widely in size.

Figure 2. Experimental unifacial scraper replicate, hard percussion. 46. Oakley, op. cit. (in note 21) fig. 2.


The unidirectional flow of materials, such as in streams and down hills, is often mentioned as a situation where unidirectional flaking can occur in nature. When products caused by this type of flaking are examined closely, however, one generally finds that any unidirectional edge damage on stone objects is conE1ned to abrasion and short, steep, transverse flake scars. This type of edge damage might be confused with scraping wear patterns, but usually lacks the longer, uniform parallel flake scars that characterize purposefully made unifacial tools.

Bifacial Flaking and Natural Edge Damage

Natural forces can create some bidirectionally flaked objects. There is no reason to predict, however, that this would result in the patterned flaking typical of human bifacial reduction. Natural forces usually randomly remove flakes to leave amorphous shapes. There is a point, of course, where a man-made tool can be so crude as to be indistinguishable from a naturally produced form. Even some of the simplest bifacial pebble tools from Olduvai Gorge, however, show a distinct patterning of flake scars to form working edges. As Carter47 has noted, the ulti- mate product of continued applications of natural force is rounded, not patterned, bifacial flaking. Patterned bifacial flaking, therefore, is a good indication of the man-made nature of specimens. On sites in the New World occupied by humans at a very early period, bifacial artifacts are most likely to be choppers, handaxes, and discoidal cores, either completely bifacially shaped or simply bidirectionally flaked on edges.

Bifacial retouch on the edges of flake tools can be distinguished from natural edge damage by the uniform placement, shapes, and sizes of flake scars. What is more, natural, random forces could seldom produce a long in- terval of bifacially retouched edge that is sharp. Natural fractures tend to produce blunt and rounded bifacial edges, because of the steep transverse nature of most natural fractures.

There is a technical explanation as to why natural fractures of edges tend to be steep and transverse across the edges of flakes. Lithic objects in nature are generally free to move or are loosely held by surrounding materials. Randomly applied forces under this condition will tend to be very oblique to the edge of the flake. Fractures then occur transversely across flake edges in the direc- tion of least mass resistance; a minimum of step-fracture termination also results.

Core Attributes

Cores are the residual products of the production of

lithic flakes. When flakes are manufactured in a patterned manner, the residual cores have attributes that demonstrate that flaking was done in a patterned manner, unlike natural random flaking. Cores shaped to form tools themselves are, of course, also diagnostic.

Evidence of the preparation of striking platforms on cores is diagnostic for activity by man, and has been discussed above for attributes of flakes. Evidence for removal of a series of flakes from a single striking platform is important. The random forces of nature are not likely to systematically remove a series of flakes. Poly- hedral cores with multiple flake scars, associated with definite striking platforms, are characteristic of flaking by man. Prismatic blade cores are especially diagnostic because of the symmetry and special manufacturing techniques that would be difficult for nature to reproduce. It should be noted, however, that the presence of an isolated polyhedral core with parallel flake scars does not demonstrate a prismatic blade industry, even though this may be good evidence of man-made flaking. For example, there are occasional blade-like cores in the Eur- asian Mousterian, but no one discusses blade industries for the New World in the same manner as for the Upper Paleolithic in Eurasia.

Nature and man both can fortuitously produce multifaceted lithic objects that are not true cores from purposeful production of flakes. The author has produced multifaceted, core-like objects with a single blow of a hammerstone, and has seen similar objects produced by the action of a bulldozer. These core-like objects, however, can be separated from true cores by the nature of the facets. A true percussion-struck core will usually have definite concoidal facets and negative cavities to match the separate force applied for individual flake removals. Facets on true cores give evidence of individual flake removals, while facets on pseudo-cores seldom have negative cavities on each flake scar at the points of the application of force. On multifaceted core-like objects there is generally no indication of impact points on the striking platform for individual flake removals.

Functional Edge Damage Use-wear patterns on edges of stone specimens can be

diagnostic of human activity. Use-wear patterns are of most value when they can be experimentally replicated using the same raw materials as the archeological specimens being examined. There is a large body of published literature on use-wear patterns, and much of the data is conflicting or inconclusive. The author's opinion is that one major problem is dealing with the edges of tools that have not been used enough to fully develop characteristic patterns of use-wear on their edges. Slight damage to the edges of tools as a result of use is difficult 47. Carter, op. cit. (in note 11) 98.


patterns of edge damage very similar to edge damage from hardwood chopping. The step-fracture terminations result because force is often applied directly into the mass of the edge of the chopping tool instead of obliquely to allow clean terminations of the fracture. As noted above, the author has observed a low incidence of multiple step-fracture terminations on naturally damaged edges, and the incidence is low because natural fractures tend to be transverse across the edge, with force not directed into the mass that would offer enough resistance to terminate the forward development of fracture planes and result in step-fracture terminations.

Patterns of edge damage are possibly some of the least useful criteria for identifying human activity, because of the many possibilities of damage of thin edges of flakes from natural forces. Whether or not the study of patterns of edge damage will become useful for indicating human activity in lithic assemblages from very early human groups remains a problem for future research. It is the author's opinion that well-developed patterns of edge damage from the longitudinal cutting function offers one of the best potentials for identifying human activity.

Bipolar Flaking

In the study of primitive lithic industries, the bipolar flaking technique is sometimes mentioned. The author's opinion5° is that bipolar flaking is an overrated subject. True bipolar fracturing, with force rebound from a hard anvil to initiate a secondary fracture plane, may be useful for pebble and cobble splitting, but this technique is not suitable for contolled flaking. Primitive man would soon so deterllline and preferably use conventional flaking, that is, the application of force at a single point in order to control fracture planes more effectively. True bipolar flaking is difficult to diagnose in lithic collections. Crude materials of this nature are not too good for demonstrating the man-made nature of lithic collections. It should be noted that simple use of a hard anvil to hold a core has advantages, and need not be generally associated with bipolar flaking. Use of a hard anvil will sometimes damage the distal end of a core in a manner that might be diagnostic, if experimentally demonstrated.

Selective Use of Raw Materials

The selective occurrence of certain types of raw material can be useful in identifying human activity at a specific location. The lack of a local source for a raw material is an argument in favor of transport by humans

50. J. B. Sollberger and L. W. Patterson, ''The Myth of Bipolar Flaking Industries,7' Newsletter of Lithic Technology 5:3 (1976) 40- 42, L. W. Patterson, ''Additional Comments on Bipolar Flaking," Flintknappers} Exchange 2:3 (1979) 21-22.

Figure 4. Experimental damage to edge as a result of chopping. Ca. 6 x magnification.

to distinguish from natural edge damage, in that only a few, small random flake scars will be present. Unless fully developed, characteristic patterns of edge wear are present, use-wear analysis cannot be diagnostic of activity by man.

Tringham et al.48 have clearly illustrated typical patterns of edge damage for cutting and scraping functions. The author has had no problems in reproducing these patterns of edge wear, such as for edge damage resulting from longitudinal cutting in the butchering of deer.49 Fully developed edge damage from the cutting function is characterized both by unifacial and bifacial sections of edge damage; scallop-shaped, short facets, and some polish and rounding on peaks of scallops.

Edge damage from the scraping function produced experimentally is somewhat like a miniature version of purposeful retouch on the unifacial edge of a scraper. It is unidirectional, with fairly uniform, parallel flake scars. These attributes would be difficult for nature to reproduce on a consistent concentrated basis, especially over long edge sections.

Functional edge damage from chopping can be distinguished from natural edge damage, even though both types of edge damage are somewhat random. Here again, to be diagnostic, the wear pattern must be fully developed by extended tool use. As shown in Figure 4, for experimental chopping of hardwood, edge damage is characterized by a wide variety of shapes and sizes of flake scars and many small, step-fracture terlllinations. Experimental chopping of bone by the author has given

48. Ruth Tringham et al., "Experimentation in the Formation of Edge Damage: A New Approach to Lithic Analysis," JFA 1 (1974) 171-196.

49. L. W. Patterson, ''Lithic Wear Patterns in Deer Butchering," Texas Archeology 19:2 ( 1975) 10- 1 1.


to a site. Another consideration is the selective occurrence of only certain types of raw materials for specimens proposed to be man-made. Man would tend to be selective in use of liffiic raw matenals, while nature would tend to fracture a wide variety of stone types in a random manner. Of course, both man and nature are limited in fracture possibilities by the physical properties of each rock type.

It should be noted that natural forces can transport lithic materials for some distance from original source areas. Transport of lithic materials by natural forces results in an alluvial deposit that becomes a new lithic source area. It is usually easy to distinguish alluvial deposits of lithic materials from concentrations of lithic materials selectively transported to a site by man, by the mixed nature of materials in natural alluvial deposits. One indication of a natural alluvial deposit of stone is that even fractured specimens will have damaged and rounded edges, from being subjected to rolling actions. T. R. Hester51 has noted that rodents can transport prehistoric flint chips to their dens, which is another natural transport phenomenon for the analyst to consider.

Experimental Veriflcation

The value of experimental verification of studies of the criteria for the attributes of man-made lithics should be noted. All types of objects in proposed early man collections can be replicated, using the same types of raw material as the original specimens. Attributes of experimental, man-made specimens can be compared with matching items in the collections under study. Possible manufacturing techniques and patterns can thus be studied with more confidence in conclusions.

Lessons from Crushed Gravel

The author has had several occasions to study the attributes of crushed chert gravel, because of intrusion on archeological sites in Texas urban areas. The reduction of gravel is done by intense mechanical crushing, which could be a severe analogy of random pressure forces generated by nature. Nature would not likely often generate such intense local pressures as mechanical crushers, but crushed chert does demonstrate what physical attributes can be expected from rock fracture by high- pressure forces not selectively directed.

Mechanical crushing of chert creates large amounts of flakes. These flakes usually lack the characteristic attributes of man-made flakes. Most flakes from gravel crushers have no bulbs of force; a large percentage do

51. Thomas R. Hester "The Natural Introduction of Mollusca in Archaeological Sites: An Example from Southern Texas," JFA 2 (1975) 274.

not have obvious striking platforms. Many of this type of flake have very flat ventral surfaces. In crushed gravel, there are few objects that resemble man-made cores. There are also no long sections of flake edges with uniform, unifacial retouch. In other words, most flakes from gravel crushers would not meet the criteria for man-made flakes and tools discussed here, and this situation is somewhat analogous to the random forces of nature.

To illustrate the general nature of flakes found in crushed gravel, a sample of 241 flakes was randomly taken from a pile of crushed chert gravel in Texas. The size range of these flakes was 20 to 40 mm. square. Thicknesses ranged 3-10 mm. Only 2% of the specimens had force bulbs, and these bulbs had odd shapes and secondary ripple lines not usually found on force bulbs in examples of man-made flakes. Only 8% of the specimens had identifiable residual striking platforms; 28% had ventral-face ripple lines, and the occurrence of ripple lines was confined to specimens of fine-grained materials. The analysis of the key attributes clearly shows that these flakes were produced by pressure flaking rather than by controlled, percussion flaking typical of early man.

In reference to comments made here on bipolar flaking, the only place where the author has observed large numbers of possible true bipolar cores is in samples of crushed gravel.

Summary

In the study of lithic collections from sites that may have been occupied by early man, care must be taken that studies are truly objective. The study of materials of early man in the New World is usually a highly emo- tional enterprise. Both proponents and critics of early man sites should base their studies on explicit technological points, or results will have little meaning. Yes- terday's "devastating criticism" often turns out to be one more set of subjective opinions. North American archeology has a long history of unfounded conservatism regarding the earliest human occupation dates in the New World. On the other hand, proponents of very early dates for sites in the New World have not always been able to offer objective arguments on why their lithic collections are man-made.

A number of possible criteria for the attributes of man- made lithics have been discussed, along with the need for more objectivity in this type of study. Fool-proof methodology is probably not possible, but studies of lithic collections supposed to have been created by humans at a very early time can be put on a more rigorous technological basis to improve objectivity. It is of little value to state that a lithic specimen does or does not look man- made to the analyst without also explicitly stating reasons


for the conclusion. It is hoped that this article will con- tribute to a more objective development of significant, man-made lithic attributes. A common set of possible criteria for man-made lithic attributes should be used, if comparisons of work by various investigators are to be meaningful. The possibility of very early man in the New World is an important area of further study, and it would be a pity if that study did not proceed in a rational manner.

Leland W. Patterson is Manager of Environmental Affairs-Engineering for Tenneco Inc., which includes the administration of cultural resource management. He is the author of numerous publications on cultural resource management, lithics technology, and the archaeology of Texas.

jfa(1983)criteria for determining the attributes of man made lithics_patterson.pdf

Documents