Pleistocene overkill and the associational critique

Journal of Archaeological Science 1986,13,51-60

Pleistocene Overkill and the Associational Critique David J. Meltzer” (Received 21 October 1984, accepted24 Muy 1985) The “associational critique”, the claim there are insufficient associations between extinct Pleistocene mammalian genera and cultural ,materials to support a model of human overkill, has been challenged by Grayson (1984). He argues that it is based on a faulty assumption regarding the sample of terminal Pleistocene megafauna, and that analysis using the radiocarbon record of extinct fauna demonstrates that there are actually more extinct genera found in archaeological association than would be expected by chance. He concludes that the associational critique is weakly based. However, his analysis warrants careful examination for, by including only radiocarbon-dated sites, and utilizing dates of questionable reliability, it is subject to sample bias. Re-analysis suggests that a rejection of the associational critique is premature. There are far too few sites showing evidence of human predation to support a model of human overkill. Keywords; PLEISTOCENE EXTINCTIONS, PLEISTOCENE MEGAFAUNA, PALAEOINDIANS, HUMAN OVERKILL, ASSOCIATIONAL CRITIQUE.

Introduction The Pleistocene overkill model (Martin, 1967, 1973) proposes that North American Clovis Palaeoindians caused the extinction of some 32 genera of large mammals. One criticism frequently voiced of this model is that it lacks archaeological corroboration. Critics contend that there are simply too few Clovis Palaeoindian kill sites to support a model of systematic human predation of extinct megafauna. The basis of this contention is the general impression that there appear to be many more terminal Pleistocene palaeontological sites than archaeological sites. This criticism has been labelled the “associational critique” (Grayson, 1984). In an examination of the associational critique, Grayson (1984) raises a number of important points. For one, he argues that the scarcity of Clovis Palaeoindian kill sites becomes a valid criticism of the overkill model only if their number is judged insufficient “given the number of terminal Pleistocene records for these taxa” (Grayson, 1984: 213-214, emphasis in original). As he put it: no matter how many fossil localities of the Glyptotherium exist, the fact that none are associated with cultural material has little bearing on overkill if all localities predate 20,000 bp (Grayson, 1984:21&215). However, no one had examined the fossil record to determine precisely how many megafaunal occurrences postdate 12,000 bp, and what percentage of these showed evidence of “Department of Anthropology, Southern Methodist University, Dallas, Texas 15275,

U.S.A. 51

0305-4403/86/010051+

10 $03.00/O

0 1986AcademicPressInc. (London) Limited

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D. J. MELTZER

human predation. All had simply assumed that there were numerous records for terminal Pleistocene faunas, and that therefore the scarcity of kill sites had some meaning. In an effort to clarify the issue, Grayson (1984) turned to radiocarbon dated fossil localities that postdate 12,000 bp, and compared the number of fossil localities with archaeological debris to the number of non-archaeological or palaeontological fossil localities. He found that mammoth (Mummuthus sp.) remains actually occur in archaeological association more often than would be expected by chance in this sample (Grayson, 1984:219). Other taxa, notably horse (Equus sp.) and camel (Cumelops sp.), may also appear in archaeological association more frequently than would be expected. Thus, he concluded that the associational critique is unfounded. Analysis The effort to go beyond simple assertions about the Pleistocene fossil record, and the results of the analysis, make Grayson’s conclusions noteworthy. However, his use of the radiocarbon record raises two questions. First, how reliable or valid are the individual radiocarbon dates that comprise the sample? Secondly, is the sample of radiocarbondated occurrences representative of terminal Pleistocene fossil localities? Grayson (1984:215, 2 19) recognized potential difficulties here, but did not address these issues in detail, arguing instead that such problems were of “much lower magnitude than those that effect more intuitive approaches to the same issues” (Grayson, 1984:220). Now that the intuitive base of the associational critique has been so thoroughly exposed, perhaps it is useful to reassess the radiocarbon record of extinct Pleistocene fauna, to determine how biases there might also influence views of the associational critique. All radiocarbon dates less than 12,000 bp on any extinct mammalian genus were used in Grayson’s (1984) analysis. The only dates excluded were those rejected by Hester (1960) in an earlier analysis of the radiocarbon dates for extinct fauna. Yet Hester (1960) had no explicit criteria for the acceptance or rejection of a radiocarbon date. Indeed, as he put it, unless “speciJicully questioned all dates and associations are accepted at ,fuce value” (Hester, 1960:63, emphasis mine). Perhaps more problematic is the fact that even Hester’s unsystematic criteria were not applied to Grayson’s entire sample. Hester had radiocarbon dates from 43 fossil localities; Grayson’s sample, based on an additional 20 years of data in Radiocarbon, included a total of 91 fossil localities. In essence, by only excluding those dates rejected by Hester (1960) Grayson tacitly assumed that the remaining 48 radiocarbon dates on fossil localities recorded since Hester’s (1960) review are valid. Such an assumption warrants further inquiry. Meltzer & Mead (1983, 1985) have developed a rating scale by which radiocarbon dates can be critically and systematically evaluated. The scale is based on two factors: the kind of material dated, and the strength of the association between the dated material and the animal fossil [see Meltzer & Mead (1985) for a detailed discussion of the rationale of the rating scheme]. This scale can be applied to determine the reliability of the radiocarbon dates used by Grayson (1984). Table 1 tallies the post-12,000 bp radiocarbon dated occurrences of extinct Pleistocene genera. Because a single locality can have more than one taxon present the total number of occurrences in Grayson’s sample (N = 137), is greater than the total number of localities (N = 91). The “All” column in Table 1 lists the number of occurrences of all genera used in Grayson’s (1984) analysis; the “Reliable” column lists the subset of those occurrences that proved to be reliably dated, using the criteria outlined in Meltzer &

PLEISTOCENE

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Table I. Posl-12.000 bp radiocarbon dated occurrences and the subset of that sample is reliably dated (“Reliable”)

I 2 3 4 5 6 I 8 9 IO 1I

Genus

All

Mammuthus Mammal Equus Camelops Nothrolheriops Symbos Tapirus Glossotherium Platygonus Castoroides Cervalces

34 30 22 I2 8 5 4 3 3 2 2

Reliable

Table 2. Megafaunal occurrences at these sites, but are not strongly Locality Aden Crater, New Mexico Nothrotheriops Big Bone Lick, Kentucky Mammathus Blackwater Draw, New Mexico Mammufhus Dry Cave, New Mexico Camelops Cave 5, Guadalupe Mtns, Texas Nothrotheriops Cave 8, Guadalupe Mtns, Texas Nothrolheriops Gypsum Cave, Nevada Equus Nothrotheriops Lehner Ranch, Arizona Mammathus Muav Cave, Arizona Nolhrotheriops Murray Springs, Arizona Mammuthus Rampart Cave, Arizona Eyuus Nothrotheriops Rappuhn, Michigan Mammut Rodney, Ontario Mammal Santa Rosa Island, California Mammuthus Tule Springs, Nevada Camelops Williams Cave, Texas Nothrotheriops

used by Grayson

( “All”),

All

Reliable

2 2 I I I 1 I 1 I 1 137

0 0 0 0 0 0 0 0 0 0 I8

Genus

5 2 2 2 7 0 0 0 0 0 0

I2 I3 I4 I5 I6 I7 I8 I9 20 2I

Megalonyx Mylohyus Arctodus Bootherium Capromeryx Hemiauchenia Holmesiana Paleolama Smilodon Tetrameryx Sum

reliably dated to post-12,000 bp (other associated with the datedsample) Evidence

for human

taxa occur

association/predation

No Strong

No No No No Strong No Strong No No Weak No Weak Weak No

54

D. J. MELTZER 7irble 3. Conringency ~ahle analysis ~$reliahly dated sites by association with artijizcts (dalafi-om Table 2; taxa numerical designations as follows: I = Mammuthus; 2 = Mammut; 3 = Equus; 4 = Camelops; 5 = Nothrotheriops) Taxa Association

with

A. Frequency

artifacts

of occurrence

1

2

3

4

5

Sum

by taxa and association

No

I

I

2

1

I

Weak

I

I

0

I

0

Strong Sum

3 5

0 2

0 2

0 2

0 I

12 3 3 18

I 4 5

I 1 2

2 0 2

1 I 2

I 0 I

12 6 18

-0.53 0.53

1.06 -1.06

-0.53 0.53

2.39* -2.39:

The

“Association”

B. Contingency

table for x2 analysist

No association Association Sum x2 = 9.94, df = 4, P < 0.05 C. Values

of adjusted

No association Association

residuals

for B -2.60** 2.60**

TFrequency data in pooled form by association. pools taxa with a “Weak” and “Strong” association. *P < 0.05. **p < 0.01.

category

Mead (1983, 1985). Those reliably dated occurrences and localities are identified in Table 2. For the full list of “All” sites, used, consult Grayson (1984: table 1). Utilizing the data in the “All” column of Table 1, Grayson developed a statistical argument that examined the distribution of occurrences with and without associated archaeological material. As noted above, based on his analysis he concluded that the associational critique is extremely weak, and that certain taxa--Mammuthus-actually occurred more often than would be expected by chance in archaeological sites. Repeating this analysis, but using instead the “Reliable” dates in Table 1, supports certain of Grayson’s conclusions. These data affirm that the sample of radiocarbondated late Pleistocene fossils is extremely small. Only 18 of the 137 occurrences postdating 12,000 bp are reliable dates. Those 18 occurrences are found in 16 sites, and include only 5 (Mammuthus, Mammut, Equus, Camelops and Nothrotheriops) of the 32 genera that became extinct at the end of the Pleistocene. The chronology of late Pleistocene extinctions is indeed poorly defined (Grayson, 1984:2 17). Following criteria in Grayson (1984), the 18 fossil occurrences are classified (Table 2) as having either “Strong”, “Weak” or “No” association between artifacts and fossil remains (a “Strong” association implies human activity was responsible for the death of the animal; a “Weak” association indicates only that the artifacts and fossil remains cooccur in the same depositional unit). Only one of the five genera (Mammuthus) shows Strong evidence of human predation. In the remaining 13 occurrences over four taxa, there are, at best, only “Weak” associations between artifacts and the extinct genera. These data are presented in tabular form in Table 3A.

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55

For purposes of analysis, the data are pooled into two categories (Table 3B): “No association” versus “Association” (= “Weak” + “Strong” association). Pooling the data in this fashion provides a stronger test of the associational critique, since it increases the frequency of fossil taxa associated with human activity. (The expected frequencies, even as a result of this pooling, fall below 1.0, but not below 0.5, in certain cells. However, the x2 criterion may be safely used in such situations: Everitt, 1977:40). x2 analysis of these data (Table 3B) shows that a significant difference exists between fossil occurrences with and without associated artifacts. Adjusted residuals (Everitt, 1977), to be read as standard normal deviates, reveal that mammoth remains occur in association with artifacts more often than would be expected by chance (Table 3C). This is the same result reached by Grayson (1984). However, no other taxa is significantly associated with artifacts. In fact, Nothrotheriops remains are significantly underrepresented in archaeological settings, as predicted by the “associational critique”. Before any significance is attached to the statistical over-representation of Mummuthus fossils in association with artifacts, it is important to recognize a factor that biases these results. As Grayson (1984:219) remarks, there is a greater tendency to sample and radiocarbon date fossils of extinct genera if they are associated with artifacts. This is particularly the case with the remains of mammoth, one of the only taxa routinely found in Pleistocene-age archaeological sites in North America, as can be demonstrated with the data in Table 4. This table tallies the number of documented mammoth occurrences with and without radiocarbon dates, versus those with and without associated artifacts. A brief explanation is warranted for the derivation of the column of chronometrically undated fossil occurrences which have been assigned to the period postdating 12,000 bp (Table 4). The assignment of the four archaeological cases is based on sound evidence that the associated Clovis artifacts postdate 12,000 bp (Haynes 1970). The 26 undated, palaeontological cases represent 25% of the total number of fossil occurrences of mammoth north of the terminal Wisconsin moraines (the “minimum estimate”, discussed below). The selection of this figure is justified below. It is sufficient to note here that this figure likely represents a reasonable, if not somewhat conservative, estimate of the number of mammoth fossils that postdate 12,000 bp. Tuhle 4. Contingmcy table analysis of Mammuthus occurrences, association and radiocarbon during: occurrences postdate 12,000 bp Association with artifacts Contingency

Reliable

radiocarbon dates

No Weak

radiocarbon dates

No radiocarbon dates

by

Sum

table for x2 analysis

No Weak + strong Sum x2 = 10.34, df = 2, P < 0.01 Values

Unreliable

partitioned

of adjusted

+ strong

1 4 5

21 8 29

26 4 30

residuals -2,95** 2.95** * < 0.05. **P < 0.01

-0.43 0.43

2,02* - 2.02*

48 16 64

56

D. J. MELTZER

x2 analysis of the data in Table 4 demonstrates that whether a site is dated is not independent of whether it has associated artifacts. Adjusted residuals analysis shows that fossil sites with associated archaeological debris are radiocarbon dated significantly more often than fossil sites without archaeological debris; conversely, palaeontological sites tend to go undated. These data further illustrate the scarcity of undated Clovis Palaeoindian sites. Only four such sites-Escapule (AZ), Kimmswick (MO), Miami (TX) and Mockingbird Gap (NM)+were identified, and while that number may not be precisely correct, it clearly illustrates the disproportion of dated versus undated fossils associated with artifacts. One can conclude from this evidence that the statistically significant over-representation of mammoth in archaeological sites simply reflects the disproportionate tendency to radiocarbon date archaeological rather than palaeontological fossil localities. This discussion has identified certain sample biases that inflate the strength of the association between artifacts and extinct mammals. The recognition of such biases enlarges our understanding of the extinctions chronology, and suggests caution in using the radiocarbon record. In fact, given the potential liabilities involved in the use of that record, it is valuable to pursue other lines of data on the association between artifacts and extinct megafauna. The discussion that follows is one such attempt, and its speculative nature is recognized at the outset. While the precise number of undated, fossil occurrences of North American Pleistocene megafauna is unknown, it is safe to assume that the figure is in the thousands [see, for example, the counts in Dreimanis (1967, 1968) Harington (1978) Hay (1923, 1924) Kurten & Anderson (1980), Skeels (I 962) and Wilson (1967)]. These undated localities comprise the bulk of the fossil record, and therefore have great potential for testing the associational critique. Nonetheless, such data must be used cautiously, for to be truly relevant, these occurrences must be terminal Wisconsin in age (Grayson, 1984:217). In fact, they must postdate 12,000 bp, the age of the Clovis Palaeoindian occupation. In the absence of chronometric dating, determining the number of North American fossil occurrences that postdate 12,000 bp cannot be done with precision. However, the timing of geological processes along with probabilistic models provide one method of deriving a sample. One can select from the thousandfold fossil occurrences, for example only those located north of the terminal Wisconsin moraines. The assumption in this procedure is that most fossil material in this area will postdate the destructive effects of glaciation, and thus postdate the age of ice retreat (Guilday, 1967). Ice retreat, however, began prior to 12,000 bp, and thus the sample must be further reduced. There are two approaches one might use for determining how many of the fossil occurrences north of the Wisconsin moraine postdate 12,000 bp. One approach is to determine what percentage of the radiocarbon-dated occurrences located north of the Wisconsin moraines postdate 12,000 bp. In the sample of reliable radiocarbon dates in Meltzer & Mead (1985), 75% of the fossils found north of the terminal Wisconsin moraine postdated 12,000 bp (which supports the assumption that few fossils predate glaciation). The other approach is to develop a probabilistic model. Martin (1973), for example, argued that if one assigned an equal probability of death, burial and discovery of a fossil population for the 5000 year span between 15,500 bp and 10,500 bp, then 25% of all fossils would postdate 12,000 bp. Later (personal communication) he argued that the percentage should be revised upward, since the expected half-life of fossils in later deposits would be higher than those in earlier deposits. Thus, more of the fossil remains would be later in age. For the sake of discussion, I will utilize Martin’s 25% figure to derive a sample of fossils postdating 12,000 bp. In comparison with the empirically derived figure of 75%,

PLEISTOCENE

OVERKILL

51

this is an extremely conservative and minimum estimate. It therefore provides a more critical test of the associational critique (for the tests that follow, patterns of significance detected in this small sample will be true as well for any larger-and perhaps more realistic-samples). The counts, by taxa, of fossil materials located north of terminal Wisconsin moraines, are listed in Table 5, and include two additional species (Panthera lea, Canis dirus) not included in the original analysis by Grayson (1984). This brings to 14 the total number of extinct genera found north of the terminal Wisconsin moraine, still less than half the total number (32) of extinct genera, though nearly three times as large as the sample (5) of reliably dated extinct genera. There are 546 fossil occurrences of these 14 genera. Using the very conservative “minimum estimate”, only 136 of those should postdate 12,000 bp. The relatively low number of genera north of the Wisconsin moraine, and the large number of occurrences of certain taxa (e.g. Mammut), reflect habitat and ecological phenomena. Limiting the analysis to areas north of the terminal moraine casts a smaller sampling net, and has the effect of reducing the number of taxa to those that inhabit northern areas. The large number of mastodon fossil occurrences reflects this animal’s habitat and range: though not obligate browsers (Kurten & Anderson, 1980), they favoured the late glacial forests of Ontario and Michigan and thus produced an abundant terminal Pleistocene fossil record in those areas following ice retreat (Dreimanis, 1967, 1968). By contrast, subtropical or temperate forms, such as the tapir, sloth and camelids, will, per force, be excluded. This geographic and taxonomic restriction should not materially effect the outcome of the analysis. If the overkill model is valid, then it must be valid for all regions and all taxa within each region. Restricting the sample to one region should not effect the validity of the test: if the associations between artifacts and extinct megafauna are present, then they should be present independent of and regardless of the exclusion of taxa that inhabit other portions of the continent. Recall from the above discussion that 33% of the reliably dated fossil occurrences (6/18) are associated with evidence of human presence; half that number showed “Strong” evidence of human predation. While recognizing, as argued above, that the association figures are likely inflated, they can be used as an a posteriori probabilistic model to illustrate an important point. For, based on these figures, one would expect at least 45 undated fossil occurrences to be associated with artifacts. If those figures are inflated, and the true expected rate of association is, say, half that, then one would expect at least 23 undated fossil occurrences to exhibit associated artifacts. Examination of all the fossil occurrences compiled for Table 5 reveals that in no instance are artifacts associated. There are, in this sample, many more terminal Pleistocene palaeontological fossil occurrences than terminal Pleistocene archaeological fossil occurrences. This is quite remarkable, since even if only 1% of those 546 undated fossil occurrences postdate 12,000 bp, then one would still expect to find at least one archaeological site with an association between artifacts and the extinct megafauna. To illustrate statistically the significance of these data, the observed and expected frequencies (the latter generated using the a posteriori probabilities based on the radiocarbon dated occurrences), are listed in Table 6. The calculated x2 value indicates there are significant differences between observed and expected occurrences with and without associated artifacts. The statistically significant lack of evidence for human predation on the extinct megafauna does not result from the absence of Palaeoindian occupation of the region. For example, as Quimby (1960:31) noted, fluted point groups and mastodons were contemporaneous on the late Pleistocene landscape of Michigan, although their remains were never physically associated. Beyond this illustration, there is ample evidence for

58

D. J. MELTZER Tuble 5. Number of fossil occurrences north (data from Dreimanis, 1967, 1968; Harington, Anderson, 1980; SkeeD, 1962; Wilson, 1967)

Genus

Number

1 Mummuthus 2 3 4 5

6 7 8 9

IO II 12

Mammut Equus Camelops Nothrotheriops Symbos Tapirus Glossotherium Piatygonus Castoroides Cervalces Megalonyx

of occurrences

of the terminul

Genus

105

13

359 17 5

14 15 16 17

15

18

7

19 20 21 22 23

26 4

1978; Hay,

Wisconsin 1923, 1924;

Number

Mylohyus Arctodus Bootherium Capromeryx Hemiauchenia Holmesiana Paleolama Smilodon Tetrameryx Panthera Cani.r Sum

Table 6. Contingency table analysis of observed pared with model (data from Table 5. statistical

moraine Kurten &

of occurrences

I I

1 3

1 546

archaeological associations model of expectationsfiom

comTable

3Al

Strong Expected Observed

association

Weak

association

23

23

0

0

No association 90 136

x2 = 69.51, df = 2, P < 0,001

an extensive Palaeoindian occupation of the region north of the terminal Wisconsin moraines. Recorded from this area are 16 Palaeoindian sites and 556 isolated eastern fluted points (Meltzer, 1984: table 7), all of which would have been contemporaneous with the Pleistocene megafauna. Again, none of these Palaeoindian remains are associated with the 136 arguably post-12,000 bp fossil remains of extinct megafauna. The associational critique appears to have merit. There are significantly fewer megafaunal occurrences in archaeological association than might be expected given the sample size. If, in fact, more than 25% of those 546 fossil localities north of the Wisconsin terminal moraine prove to postdate 12,000 bp, then this conclusion gains even greater strength. Conclusion The associational critique of the Pleistocene overkill theory, that there are insufficient numbers of kill sites to support a model of systematic and extensive human predation, was challenged by Grayson (1984). He rightly argued such a critique was valid only if it could be demonstrated that the number of kill sites was much smaller than would be expected by chance given a known sample of terminal Pleistocene fossil occurrences. From his analysis of the radiocarbon-dated occurrences of Pleistocene megafauna, he concluded that there were, in fact, sufficient numbers of megafaunal occurrences in archaeological sites to reject the associational critique of the Pleistocene overkill model.

PLEISTOCENE OVERKILL

59

Yet this analysis, in turn, incorporated certain biases in the radiocarbon record, such as the inclusion of unreliable dates and the disproportionate tendency to chronometrically date archaeological fossil occurrences. The net result of this was to inflate the relative number of extinct mammals in archaeological settings, thereby weakening the case for rejection of the associational critique. In this paper I have reanalysed the associational critique, using a sample of nonchronometrically dated fossil occurrences. This analysis is recognizably limited by the strength of the underlying assumptions, but these assumptions appear reasonable, and have the added virtue of being testable. Using this sample of undated fossil occurrences proved quite enlightening. It suggests that there are, indeed, many terminal Wisconsin fossil occurrences-136 was the projected minimum number for the area located north of the terminal Wisconsin moraine. It further indicated that at least 45 of those fossil localities should contain associations between artifacts and extinct fauna1 remains. Yet it demonstrated that in no single instance was there a site where artifacts were associated with the fossil taxa. This despite the fact that, even at these minimum limits, this sample was seven times larger than the one used by Grayson (1984), which appeared to show a significant pattern of fossil material with associated artifacts. For this sample, the conclusion is clear: there is insufficient archaeological evidence of human predation to support the overkill model. Acknowledgements I would like to thank Jeffrey S. Girard for aid in compiling the data, and Harold J. Hietala, Richard G. Klein, Paul S. Martin and especially Donald K. Grayson for helpful comments on this paper. References Dreimanis, A. (1967). Mastodons, geologic age and extinction in Ontario, Canada. Canadian Journal of Earth Sciences 4,6633675.

Dreimanis, A. (1968). Extinction of mastodons in eastern North America: testing a new climatic environmental hypothesis. The Ohio Journal qf Science 68,257-272. Everitt, B. (1977). The Analysis of Contingency Tables. London: Chapman and Hall. Grayson, D. K. (1984). Archaeological associations with extinct Pleistocenemammals in North America. Journul of Archaeological Science 11,2133221. Guilday, J. E. (1967). Differential extinction during Late-Pleistocene and Recent times. In (P. S. Martin & H. E. Wright, Eds) Pleistocene Extinctions; the Search for a Cause. Yale University Press:New Haven, pp. 121-140. Harington, C. R. (1978). Quaternary vertebrate faunas of Canada and Alaska and their suggested chronological sequence.Syllogeus 15, l-105. Hay, 0. P. (1923). The Pleistoceneof North America and its vertebrated animals from the states east of the Mississippi River and from the Canadian Provinces east of Longitude 95”. Carnegie Institute of Washington,

Publication

322.

Hay, 0. P. (1924). The Pleistoceneof the Middle Region of North America and its vertebrated animals. Curnegie Institute of Washington, Publication 322A. Haynes, C. V. (1970). Geochronology of man-mammoth sitesand their bearing on the origin of the Llano Complex. In (W. Dort & J. Jones, Eds) Pleistocene and Recent environments of the central Great Plains. Wichita: University of Kansas Press,pp. 77-92. Hester, J. (1960). Late Pleistoceneextinction and radiocarbon dating. American Antiquity 26, 5877. Kurten, B. & Anderson, E. (1980). Pleistocene mammals of North America. New York: Columbia University Press. Martin, P. S. (1967). Prehistoric overkill. In (P. S. Martin and H. E. Wright, Eds) Pleistocene E,xtinctions: the Search for a Cause. New Haven: Yale University Press,pp. 75-120.

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Martin, P. S. (1973). The discovery of America. Science 179,969%974. Meltzer, D. (1984). Late Pleistocene human adaptations in eastern North America. Unpublished Ph.D. dissertation, Department of Anthropology, University of Washington. Meltzer, D. J. & Mead, J. I. (1983). The timing of late Pleistocene mammalian extinctions in North America. Quaternary Research 19, 130-135. Meltzer, D. J. & Mead, J. I. (1985). Dating late Pleistocene extinctions: theoretical issues, analytical bias and substantive results. In (J. I. Mead & D. J. Meltzer, Eds) Man in lute glacial North America. The Center for the Study of Early Man, Research Sites, University of Maine, Orono, pp. 1455173. Quimby, G. I. (1960). Indian life in the Upper Greut Lakes. Chicago: University of Chicago Press. Skeels, M. A. (1962). The mammoths and mastodons of Michigan. Papers Michigan Acudemy of Science, Arts and Letters47, 101-133. Wilson, R. L. (1967). The Pleistocene vertebrates of Michigan. Papers Michigan Academy qf Science, Arts and Letters 52, 197-234.