Stratigraphic and geochronologic contexts of mammoth (Mammuthus)

Quaternary International 142–143 (2006) 87–106 

Stratigraphic and geochronologic contexts ofmammoth 

(Mammuthus) and other Pleistocene fauna, Upper Missouri Basin 

(northern Great Plains and Rocky Mountains), U.S.A. 

Abstract 

Christopher L. Hill 

Department of Anthropology, Boise State University, 1910 University Drive, Boise, Idaho 83725-1950, USA 

Available online 10 May 2005 

Mammoth fossils and other Pleistocene vertebrates from the Upper Missouri Basin, in the northern Plains and Rocky Mountains 

ofthe western interior ofNorth America, have been dated to the late Pleistocene and are associated with Wisconsinan deposits. 

Mammoth remains have also been found in older stratigraphic contexts. For example, Mammuthus columbi and other fossils from 

the Doeden Locality are in pre-Wisconsinan terrace gravels along the Yellowstone River; the deposits are likely Illinoian or 

Sangamonian. Faunas that appear to be associated with the Wisconsinan interstadial, before the Last Glacial Maximum, are found 

in intermountain valleys and mountain settings (the Merrell Locality, Blacktail Cave, Natural Trap Cave) and on the Plains in both 

glaciated and unglaciated regions (Box Creek, Wibaux gravel pit). Localities containing faunas dated to the time interval from about 

the Last Glacial Maximum to the end ofthe Younger Dryas chronozone (late Wisconsinan) include the youngest fossil-bearing 

strata at Merrell, Blacktail Cave, Natural Trap Cave; deposits at Sheep Rock Spring, Indian Creek, MacHaffie, False Cougar Cave, 

Shield Trap Cave; and mammoths found at Sun River, Glendive, Colby, and the Deer Creek drainage. 

r 2005 Elsevier Ltd and INQUA. All rights reserved. 

1. Introduction 

Fossil remains ofmammoth (Mammuthus) have been 

recovered from a variety of stratigraphic and chronologic 

contexts in the Upper Missouri River Basin. 

Situated in the western interior ofNorth America 

(Fig. 1), the Upper Missouri region consists ofthe 

watersheds ofthe Missouri and Yellowstone Rivers 

upstream from their confluence (Fig. 2). Mammoth 

fossils have been found in both unglaciated and 

glaciated areas ofthe Northern Great Plains as well as 

in valley deposits within the Rocky Mountains. Depositional 

environments associated with the stratigraphic 

contexts include paludal-lacustrine and swamp-bog 

settings, caves and rockshelters, alluvial deposits and 

fluvial terraces, uplands associated with eolian deposition 

and paleosols, and debris flows. Where stratigraphic 

and chronologic indicators are available, they 

E-mail address: chill2@boisestate.edu. 

ARTICLE IN PRESS 

1040-6182/$ - see front matter r 2005 Elsevier Ltd and INQUA. All rights reserved. 

doi:10.1016/j.quaint.2005.03.007 

seem to show that the mammoth remains date to the 

middle and late Pleistocene. 

2. Mammoth localities 

An inventory ofmammoth remains recovered from 

the Upper Missouri River Basin is presented in Table 1. 

The fossil localities containing mammoth remains and 

other Pleistocene fauna can be organized by geographic 

area, principally by regional drainage basins. These 

regions include the headwaters ofthe Missouri River, 

the glacial Lake Great Falls Basin, the Missouri River 

system east ofGreat Falls, and the drainage ofthe 

Yellowstone River (Fig. 2). 

2.1. Missouri headwaters: Three Rivers Basin 

The stream systems ofthe Gallatin, Madison, and 

Jefferson Rivers form the Three Rivers Basin in the

88 

vicinity ofDillon, Montana (Fig. 2). Fluvial deposits in 

the Gallatin Valley (between Dillon and Livingstone, 

Fig. 2) contain remains of Mammuthus (Fig. 3). Fossils 

of M. columbi have also been collected from Alder 

Gulch (Hay, 1924; Hayden, 1872) (Fig. 2). Other late 

Pleistocene fauna, including Miracinonyx ð¼ AcinonyxÞ, 

Camelops, Bison, and Ovis have been collected from the 

Sheep Rock Spring locality (Fig. 2) (Wilson and Davis, 

1994, 2002). Fragments of Mammuthus have been 

reported from the Horse Prairie area (Bonnichsen et 

al., 1987, 1990, 1992; Turner et al., 1987, 1988). A 

Rancholabrean faunal assemblage containing mammoth 

fossils has been recovered from the Merrell Locality 

(Fig. 2), in Centennial Valley, from swamp (Fig. 4), 

paludal-lacustrine, fluvial, and debris flow (Figs. 5, 6) 

environments (Dundas, 1990, 1992; Albanese et al., 

1995; Hill et al., 1995; Hill and Albanese, 1996; Dundas 

et al., 1996; Hill, 1999a, b). The mammalian fauna 

includes Mammuthus, Equus, Camelops, Odocoileus, 


C.L. Hill / Quaternary International 142– 143 (2006) 87–106 

Fig. 1. Location ofthe Upper Missouri River basin, in the interior ofwestern North America. Note also location ofcontinental glaciers after the 

Last Glacial Maximum. 

Antilocapra, Bison, Ursus, Homotherium serum, Canis 

latrans, C. lupus, Spermophilis, Castor canadensis, and 

Ondatra zibethicus (cf. Dundas et al., 1996). 

2.2. Glacial Lake Great Falls Basin 

Glacial Lake Great Falls was formed when the 

Laurentide Ice Sheet (LIS) blocked the drainage ofthe 

Missouri River (Calhoun, 1906; Alden, 1932; Montagne, 

1972; Hill, 2000; Feathers and Hill, 2003) (Fig. 7). 

Luminescence measurements oflaminated lacustrine 

silts and overlying sands adjacent to Holter Lake (Hill 

and Valppu, 1997) indicate the youngest stage ofglacial 

Lake Great Falls has an age ofaround 15,000– 

13,000 OSL BP (UW355 and UW356, Feathers and Hill, 

2003). This would imply that a lobe ofthe LIS extended 

to and blocked the Missouri River during the later part 

ofthe Wisconsin Episode (Karrow et al., 2000; Hill and 

Feathers, 2002; Feathers and Hill, 2003).

Localities containing Pleistocene mammalian remains 

are present in the glacial Lake Great Falls Basin (Figs. 2, 

7). The stratigraphy along Indian Creek (Fig. 2) 

contains both the late Pleistocene Glacier Peak and 

middle Holocene Mount Mazama tephras along with 

faunal remains and a series of artifact assemblages 

(Albanese and Frison, 1995). Fauna overlying the 

Glacier Peak tephra (ca. 11,125 14 C BP) associated with 

a date ofabout 10,980 14 CBP (Table 2) include Bison, 

Ovis, Marmota, and Sylvilagus (Davis and Baumler, 

2000). A separate terminal Pleistocene assemblage 

contains Bison, Marmota flaviventris, Sylvilagus, Cynomys 

ludovicianus, and Microtus (Davis and Baumler, 

2000). In this same general region, remains of Mammuthus 

and Mammut americana have been recovered 

from the Diamond City-Confederate Gulch area, and 

Mammuthus has been found near Helena (Figs. 2, 7) and 

close by at Spokane Creek and Spokane Bar (Douglass, 

1908; Freudenberg, 1922; Hay, 1924, 1927; Madden, 

1981). A mammoth tooth from Spokane Bar is regarded 

as possibly the northernmost record for Mammuthus 

imperator (cf. Hay, 1927; Madden, 1981: p. 206). 

However, M. imperator has been reported north ofthe 

Missouri Basin in Alberta at Bindloss, Empress, and 

Medicine Hat (Harington and Shackleton, 1978). The 

Bindloss specimen is now attributed to M. columbi (Hills 

and Harington, 2003). Also near Helena, Bison has been 

recovered from Upper Holter Lake (Melton and Davis, 

1999). The nearby MacHaffie site (Fig. 7) contains a 

Folsom artifact component associated with a bone 


C.L. Hill / Quaternary International 142– 143 (2006) 87–106 89 

Fig. 2. Missouri and Yellowstone Rivers, showing locations ofsome localities mentioned in text. 

collagen age on Bison of10,390 14 C BP (Beta-159167, 

Davis et al. 2002; Table 2). 

Blacktail Cave, situated near the South Fork ofthe 

Dearborn River (Figs. 2, 7), contains a stratigraphic 

sequence with radiocarbon ages ranging from about 

37,000–10,000 14 CBP (Hill, 1996, 2000, 2001; Table 2). 

A phalanx from a bear (Ursidae) recovered from talus 

beneath a travertine, near the top ofthe stratigraphic 

sequence, was dated to 10,930780 14 C BP (GX-21559). 

Sediments containing higher amounts offine clastics, 

overlain by travertine, contained an artiodactyl dated to 

10,2707115 14 C BP (GX-21556) and a bovid dated to 

11,240780 14 C BP (GX-21557). An Equus phalanx 

recovered slightly above a deposit ofsands and 

gravels dates to 27,2007370 14 C BP (GX-21558). The 

lowest sediments in the sequence consist ofmuds and 

clays interpreted as having been deposited in a cave 

pool, indicating higher groundwater levels around 

37,4007790 14 C BP (Beta-106101), based on collagen 

from Marmota flaviventris. Faunal remains from these 

deposits have been reported in Davis et al. (1996) and 

have also been reappraised independently by Dundas 

and Hill (Hill, 2001). Large-to-medium-sized mammals 

include Bootherium/Symbos (Symbos cavifrons in 

Melton, 1979; Bootherium bombifrons in Davis et al., 

1996), Bison occidentalis (Melton and Davis, 1999), 

Equus cf. conversidens, Odocoileus, Antilocapra, Ursidae, 

Canis lupus, C. latrans, Vulpes, Gulo gulo and Taxidea 

taxus. The presence of Mammuthus and Arctodus at 

Blacktail Cave reported by Davis et al. (1996) cannot be

90 

confirmed. Smaller mammal taxa include Cynomys, 

Marmota flaviventris, M. caligata, Thomomys, Castor 

canadensis, Spermophilus, Microtus, Neotoma, N. cf. 

cinera, Phenacomys albipes and Lepus. 



Table 1 

List ofmajor mammoth and other Pleistocene vertebrate localities in the Upper Missouri River Basin 

1. Missouri Headwaters (Three Rivers Basin, Southwest Montana) 

Merrell Locality, Centennial Valley (Dundas, 1992; Dundas et al., 1996; Melton and Davis, 1999) 

Horse Prairie (Bonnichsen et al., 1987, 1990, 1992; Turner et al., 1987, 1988) 

Alder Gulch-Virginia City Mammoth (Hayden, 1872; Hay, 1924) 

Gallatin Valley (JTL, Belgrade) Mammoth (this paper) 

Sheep Rock Spring (Wilson and Davis, 1994, 2002; Melton and Davis, 1999) 

2. Glacial Lake Great Falls Basin (Northwest Montana, East ofContinental Divide) 

Indian Creek (Melton and Davis, 1999) 

Townsend Valley-Helena Area (Douglass, 1908) 

Diamond City (Hay, 1924) 

Washburn (Helena) Mammoth (G. Langeford in Hay, 1924) 

Steitz (Helena) Proboscidean (Hay, 1924) 

Spokane Bar (Sponambar, Helena) Mammoth (Freudenberg, 1922; Hay, 1924, 1927; Madden, 1981) 

Spokane Creek Proboscidean (Hay, 1927) 

Upper Holter Lake (Melton and Davis, 1999) 

MacHaffie (Melton and Davis, 1999) 

Blacktail Cave (Melton, 1979; Graham et al., 1987; Davis et al., 1996; Hill, 1996, 2000, 2001; Melton and Davis, 1999) 

Coulee near Sun River (1954, Neal-Lemke-Maughn studies) Mammoth (Maughn, 1955, U.S.G.S. archives; E. Lewis, 1955, U.S.G.S. archives) 

Coulee near Sun River (1965, Neal-Mudge-Mudge studies) Mammoth (Marsters et al., 1969; U.S.G.S. archives) 

Vaughn-Congres Pit Mammoth (R.W. Lemke, U.S.G.S. archives) 

Lewis and Clark County-Yale (vertebrate paleontology catalog, Peabody Museum ofNatural History, Yale University) 

Valier Mammoth (R.A. Wood in Hay, 1924) 

Missouri River (Hay, 1914; Dudley, 1988) 

3. Central and Eastern Montana, Missouri Basin 

Havre Mammoth (Hay, 1924) 

Havre Gravel Pit (Beck-Ankerland Garage) (Fullerton and Colton, 1986; U.S.G.S. archives) 

Simonsen Ranch (Saco-Hinsdale) Mammoth (Davis, 1975, 1986) 

Tiger Butte Mammoth (fossil locality 5, Jensen and Varnes, 1964) 

Wiota Gravels-Frazer Mammoth/Equus (Jensen and Varnes, 1964) 

West Nashua Equus (Jensen and Varnes, 1964) 

Glasgow Equus (Jensen and Varnes, 1964) 

Fort Peck Gravels Bison (Rasmussen, 1974) 

Red Water Creek (Axtell) Mammoth (Hay, 1924) 

Outlook Musk Ox (Neas, 1990) 

Box Creek Locality (this paper) 

Lisk Creek Bison (Melton and Davis, 1999) 

4. Yellowstone Drainage 

Anzick-Wilsall (Taylor, 1969; Laren and Bonnichsen, 1974; Jones and Bonnichsen, 1994; Stafford, 1999; Owsley and Hunt, 2001) 

False Cougar Cave (Bonnichsen, 1985; Bonnichsen et al., 1986; Graham et al., 1987) 

Shield Trap (Bonnichsen et al., 1986; Graham et al., 1987) 

Pryor Creek Mastodon (Hay, 1924) 

Rosebud Mammoth (Winchell, 1882; Hay, 1924) 

Tongue River-Ashland Mammoth (Hay, 1924) 

Tongue River-Bass Mammoth (Bass, 1932) 

Tongue River Bison (Melton and Davis, 1999) 

Powder River-Kimball/Hockets (Hay, 1924) 

Mill Iron Local Fauna (Walker and Frison, 1996) 

Wibaux Gravel Pit Proboscidean (Hill, 2003) 

South Fork Deer Creek Mammoth, near Lindsay (Davis and Wilson, 1985; Davis, 1986; Hill and Davis 1998; Huber and Hill, 2003) 

Richey Area Mammoth (Madden, 1981) 

Doeden Gravel Pit (Hill, 1998; Melton and Davis, 1999; Wilson and Hill, 2000, 2002) 

Payes Musk Ox (McDonald and Ray, 1989) 

Glendive-Crisafulli Gravel Pit (Hill, 2003) 

Glendive-Canal Mammoth (Hay, 1924) 

Natural Trap Cave (Chomko and Gilbert, 1987) 

Colby Mammoth (Frison and Todd, 1986, 2001) 

Research connected with studies by the United States 

Geological Survey (U.S.G.S.) during the 1950s and 

1960s in the Sun River area along the eastern front of 

the Rocky Mountains in Montana (Table 1, Figs. 2, 6),

Fig. 4. Merrell Locality mammoth (Mammuthus columbi). Mammoth 

tooth found along the interface of stratum A and stratum B (swamp 

deposits). 

led to the documentation ofthree localities containing 

the remains of Mammuthus (Figs. 7–9). Two localities 

are situated in a coulee west ofAugusta, while the other 

locality is a gravel pit west ofVaughn (Marsters et al., 

1969) (Fig. 7). One ofthe mammoths (attributed to 

Mammuthus columbi) found west of Augusta was 

embedded in organic-rich deposits dated to about 

11,500 14 C BP (W-1753; Table 2). Other proboscidean 

remains mostly attributable to Mammuthus from this 



Fig. 3. Gallatin Valley mammoth. 

region are in the collections ofthe museum in Shelby, 

Montana, and the Peabody Museum ofNatural History 

at Yale University, New Haven, Connecticut. Hay 

(1914, 1924) also records remains of Mammuthus from 

near Valier (Fig. 7), and along the Missouri River 

(designated M. columbi jeffersonii in Dudley, 1988). In 

the Marias River Valley near Elwell (Figs. 2, 6) a 

fragment of bone, recovered near a tephra and above 

Laurentide till, with an age of11,170 14 C BP (Beta- 

159200, Table 2) constrains the Late Pleistocene 

deglaciation chronology for this region. 

2.3. Northern Montana, East of the Great Falls Basin 

East ofGreat Falls in northern Montana (Fig. 2), the 

drainage ofthe Missouri River contains Pleistocene 

deposits with fossils of mammoth and other Pleistocene 

fauna. Within the Milk River drainage, there are several 

gravel pits in the vicinity ofFrazer (Fig. 2) with 

Pleistocene fauna (Pecora et al., 1957; Fullerton and 

Colton, 1986). These finds are often associated with 

Pleistocene terrace gravels (Pecora et al., 1957). Mammuthus, 

Equus, and Camelops have been recovered in 

alluvial deposits underlying a middle Pleistocene till at 

Havre (Fullerton and Colton, 1986) (Fig. 2). Remains of 

Mammuthus were recovered from possible glacial outwash 

gravels in the region between Havre and Frazer 

(Davis, 1975, 1986). 

Fossil of Mammuthus and Equus found in the Wiota 

gravels near Frazer (Fig. 2) at Tiger Butte are attributed 

to ‘‘Mammuthus boreus Hay (Mammuthus primigenius 

Blumenbach– Parelephas jeffersoni Osborne)’’ (Jensen 

and Varnes, 1964). Remains of Mammuthus and Equus 

from south of Frazer were found in gravel overlain by a 

till (Jensen and Varnes, 1964). A faunal assemblage

92 

Fig. 6. Close-up ofdebris flow deposit containing mammoth teeth and 

bones, Merrell Locality. 

containing Mammuthus has also been recovered from 

near Box Creek (Figs. 2, 10). The metric attributes ofthe 

mammoth tooth indicate an affiliation with M. columbi 

(based on M6(M3) with plates ½number oflamellaeŠ ¼ 

18 þ½number ofplates abraded by wear ¼ 14þŠ and lamellar 

frequency ¼ 7 9, Fig. 10), while tusk fragments 

provide an age of33,2807320 14 C BP (Beta-155639) and 

32,6607620 14 C BP (SR-6023; Table 2). A possible 

Bison latifrons has been radiocarbon dated to 

19,930770 14 CBP (Melton and Davis, 1999; Table 2) 

from this region, and there are other reports of 

Mammuthus (Hay, 1924) and Ovibos moschatus (Neas, 

1990). 



Fig. 5. Stratigraphic context ofmammoth tooth in debris flow (stratum D) at the Merrell Locality. 

2.4. Yellowstone River Basin 

The Yellowstone River Basin extends over the southern 

part ofthe Upper Missouri River drainage including 

northern Wyoming and southern and eastern Montana 

(Figs. 1, 2). Pleistocene faunal localities are known from: 

(1) north ofLivingston; (2) the Pryor Mountain region 

south ofBillings; (3) valleys ofnorthward flowing 

tributaries such as the Big Horn, Tongue, and Powder 

Rivers and Beaver Creek; (4) drainages ofsoutheastward 

flowing streams such as South Fork Deer Creek, 

close to Lindsay; and, (5) terrace deposits along the 

Yellowstone River valley itself, such as around Miles 

City and Glendive (Fig. 2). Several occurrences of 

Mammuthus have been reported from the Livingston 

area (Fig. 2), including the possible foreshafts manufactured 

from mammoth bone associated with Clovis 

artifacts at the Anzick site (Taylor, 1969; Lahren 

and Bonnichsen, 1974; Jones and Bonnichsen, 1994; 

Stafford, 1999; Owsley and Hunt, 2001). 

In the Pryor Mountains, south ofBillings (Fig. 2), 

Pleistocene mammals have been recovered from False 

Cougar Cave and Shield Trap Cave (Bonnichsen, 1985; 

Bonnichsen et al., 1986; Graham et al., 1987). The 

lowest stratum at False Cougar Cave is interpreted as a 

cut-and-fill sequence offluvial deposits (Bonnichsen et 

al., 1986) and contains late Pleistocene small mammal 

remains. There are two radiocarbon dates from within 

an overlying deposit of14,5907300 and 10,5307 

140 14 CBP (Table 2). Shield Trap Cave contains a 

late Pleistocene or early Holocene faunal assemblage, 

based on a radiocarbon age ofabout 9230 14 CBP 

(Bonnichsen et al., 1986; Graham et al., 1987). Also in 

this region ofthe Pryor Mountains and the Big Horn 

Mountains, Natural Trap Cave (Fig. 2) contains a 

significant Pleistocene fauna, including Mammuthus, 

Camelops, Equus, Bootherium ð¼ SymbosÞ, Arctodus,

Miracinonyx ð¼ AcinonyxÞ and Panthera (Chomko and 

Gilbert, 1987). There are seven radiocarbon dates 

ranging from 21,370 to 10,930 14 CBP (Table 2) indicating 

the assemblage reflects Last Glacial Maximum and 

late-glacial biotic communities. 

South ofthe Pryor Mountains and east ofthe Big 

Horn River (Fig. 2), mammoth (Mammuthus columbi) 

remains have been found in association with Clovis 

artifacts at the Colby site (Frison and Todd, 1986, 

2001). An age of11,2007220 14 C BP (collagen, RL-392) 

and an age of10,8647141 14 C BP (apatite, SMU-254) 



Fig. 7. Glacial Lake Great Falls and localities mentioned in text. 

are associated with this locality, which also contains a 

late Pleistocene mammalian faunal assemblage with 

Lepus, Equus conversidens, Antilocapra americana, 

Camelops, andBison (Walker and Frison, 1996). 

The valleys ofstreams south ofthe Yellowstone River 

contain evidence for the presence of Mammuthus and 

Bison within the Tongue River valley (Winchell, 1882; 

Hay, 1924; Bass, 1932; Melton and Davis, 1999), the 

Powder River valley (Hay, 1924), the Beaver Creek 

valley near Wibaux (Hill, 2003), and within the Little 

Missouri River drainage (Fig. 2)(Frison, 1996). A molar

94 



Table 2 

Selected Late Pleistocene radiocarbon ages associated with mammoth fossils and other fauna from the Upper Missouri Basin 

Locality Age Laboratory number Material Reference 

Pre-Late Wisconsinan 

Merrell Locality 49,35071,500 Beta-116519 Collagen alkali Hill (1999b) 

Merrell Locality 441,940 Beta-83614 Humates Dundas et al. (1996) 

Merrell Locality 36,5207710 Beta-74032 Organic sediment Hill (1999b) 

Merrell Locality 433,990 Beta-36206 Bone collagen Dundas (1992) 

Merrell Locality 32,4707270 Beta-111325 Bone collagen Hill (1999b) 

Merrell Locality 25,0307510 Beta-36205 Bone collagen Dundas (1992) 

Blacktail Cave 37,4007790 Beta-106101 Collagen Hill (2001) 

Blacktail Cave 27,2007370 GX-21558 Collagen Hill (2001) 

Beaver Creek 26,0007120 SR-6086 XAD-gelatin, KOH-collagen Hill (2003) 

Box Creek 33,6607620 SR-6023 XAD-gelatin, KOH-collagen This paper 

Box Creek 33,2807320 Beta-155639 Collagen This paper 

Approximately Last Glacial Maximum 

Merrell Locality 21,5307100 Beta-118755 Collagen, alkali Hill (1999b) 

Merrell Locality 19,290790 Beta-77826 Collagen, alkali Albanese et al. (1995) 

Glendive Mammoth 20,470780 Beta-155642 Collagen extraction with alkali Hill (2003) 

Lisk Creek 19,930790 Beta-122116 Collagen Melton and Davis (1999) 

Natural Trap Cave 21,370+830–920 Dicarb-1686 Collagen Chomko and Gilbert (1987) 

Natural Trap Cave 20,2507275 Dicarb-1687 Collagen Chomko and Gilbert (1987) 

Natural Trap Cave 17,8707230 Dicarb-1686 Collagen Chomko and Gilbert (1987) 


Late Glacial to Younger Dryas 

Sheep Rock 10,220740 Beta-164532 Charred material This paper 

Sheep Rock 10,100740 Beta-164530 Charred material This paper 

Indian Creek 11,1257130 Beta-4951 Plant remains with Glacial Peak tephra Davis and Grieser (1992) 

Indian Creek 10,9807110 Beta-4619 Charcoal Davis and Grieser (1992) 


Indian Creek 10,410760 Beta-98679 Collagen Davis and Baumler (2000) 


MacHaffie 10,390740 Beta-159167 Collagen Davis et al. (2002) 

MacHaffie 10,090750 Beta-159058 Organics Davis et al. (2002) 




Sun River 11,5007300 W-1753 Organic sediment Marsters et al. (1969) 

Marias River 11,170750 Beta-159200 Collagen, alkali This paper 

Anzick 11,550760 Stafford Labs Gelatin Owsley and Hunt (2001) 

Anzick 10,940790 AA-2981 Glycine Stafford (1994) 

Anzick 10,8207100 AA-2979 Glutamic acid Stafford (1994) 

Anzick 10,7107100 AA-2980 Hydrocyproline Stafford (1994) 

Anzick 10,5007400 AA-313B Gelatin Stafford (1994) 

Anzick 10,3707130 AA-2982 Alanine Stafford (1994) 

Anzick 10,2407120 AA-2978 Aspartic acid Stafford (1994) 

False Cougar Cave 14,5907300 Beta-5752 Charcoal Bonnichsen et al. (1986) 

False Cougar Cave 10,5307140 SI-5289 Charcoal Bonnichsen et al. (1986) 


Natural Trap Cave 12,7777900 Collagen Rushkin in Chomko and Gilbert (1987) 

Natural Trap Cave 10,9307300 Collagen Rushkin in Chomko and Gilbert (1987) 

Colby Mammoth 11,2007220 RL-392 Collagen Frison and Todd (1986) 

Colby Mammoth 10,8647141 SMU-254 Apatite Frison and Todd (1986) 

Colby Mammoth 8,7197392 SMU-278 Collagen Frison and Todd (1986) 

Mill Iron 11,5707170 NZA-625 Charcoal Frison (1996) 


Mill Iron 11,3607130 Beta-20111 Charcoal Frison (1996) 






Mill Iron 10,770785 AA-3669 Charcoal Frison (1996) 

Deer Creek Mammoth 12,330750 SR-5576 XAD-gelatin, KOH-collagen Hill (2003)

Table 2 (continued ) 

discovered in the vicinity ofthe Powder River was 

identified as Mammuthus imperator (Hay, 1924). The 

Mill Iron Site (Fig. 2) local fauna is associated with 

dates ranging from about 11,570 to 10,760 14 CBP 

(Frison, 1996; Walker and Frison, 1996; Table 2). The 

deposits at Mill Iron are in an upland setting within the 

Humbolt Creek drainage (Albanese, 1996). The butte is 

formed by a sedimentary sequence with more than 2 m 

ofQuaternary deposits overlying bedrock. Bones and 

artifacts overlie fluvial and colluvial deposits and lie 

below colluvial and eolian sediments (Albanese, 1996). 

Bison bison cf. antiquus represents the only extinct taxon, 

other than a proboscidean rib fragment assigned to cf. 

Mammuthus (Walker and Frison, 1996). The rib 

fragment at Mill Iron appears to have been modified 

into an artifact. Other taxa in the fauna are: cf. Rana, 

Pituophus melanoleucus, Spermophilus cf. tridecemlineatus 

(considered to be intrusive), Thomomys talpoides 

(also possibly intrusive), Reithrodontomys cf. megalotis, 



Locality Age Laboratory number Material Reference 

Deer Creek Mammoth 12,0057350 S-1918 Collagen Davis and Wilson (1985) 

Deer Creek Mammoth 11,500780 Beta-10231 Collagen Hill and Davis (1998) 

Deer Creek Mammoth 11,0607225 I-9220 Collagen Davis and Wilson (1985) 

Deer Creek Mammoth 10,7807290 WSU-652 Collagen Davis and Wilson (1985) 

Deer Creek Mammoth 95707135 I-7028 Collagen Davis and Wilson (1985) 

Stratigraphic Ages 

Sheep Rock 9910770 Beta-77827 Charred material This paper 

Sheep Rock 9070760 Beta-164531 Organic sediment This paper 

Sheep Rock 5510760 Beta-164532 Organic sediment This paper 

Elkhorn Mountains 6550740 Beta-155641 Plant material near tephra This paper 

OTL Ridge 11,415735 SR-6089 Humic acids Hill (2003) 

OTL Ridge 9330780 Beta-155708 Organic sediment Hill (2003) 

OTL Ridge 9540790 Beta-155709 Organic sediment Hill (2003) 

Fig. 8. Mammoth mandible from the Sun River area (U.S.G.S. archives). 

Peromyscus cf. maniculatus, Microtus longicaudus and 

M. ochrogaster (Walker and Frison, 1996). The presence 

of Microtus longicaudus (which has not been reported 

from the extant, present-day fauna) suggests the 

possibility ofan expanded montane habitat, possibly 

an open parkland environment, in the region during the 

last glacial-interglacial transition. 

Stream valleys north ofthe Yellowstone River also 

contain Pleistocene fossils. These include isolated 

Mammuthus remains (Madden, 1981), as well as the 

nearly complete M. columbi skeleton (Fig. 11) found in 

the upland northeast ofLindsay (Fig. 2), in the South 

Fork Deer Creek drainage (Davis and Wilson, 1985; Hill 

and Davis, 1998; Huber and Hill, 2003). There is a set of 

radiocarbon dates for the remains of this mammoth 

ranging from about 12,330 to 9,490 14 CBP (Table 2), 

including a radiocarbon age on collagen of11,5007 

80 14 C BP (Beta-102031, Hill and Davis, 1998) and an 

age of12,330750 14 C BP (SR-5576) on XAD-gelatin

96 

Fig. 9. Occlusial surfaces of mammoth molars from Sun River area 

(U.S.G.S. archives). 

Fig. 10. Occlusial surface of Box Creek mammoth. 

(Hill, 2003). The mammoth fossils were recovered in 

eolian silts under several buried paleosols. The silts 

contain a pollen spectra reflecting the presence ofboth 

arboreal and nonarboreal vegetation (Huber and Hill, 



Fig. 11. Lower jaw and molars ofmammoth discovered in the uplands 

ofthe South Fork ofDeer Creek. 

Fig. 12. Loess deposits at OTL ridge with paleosols radiocarbon dated 

to the Pleistocene–Holocene boundary. 

2003). The presence of Pinus, Betula, and Salix and 

open-ground herbaceous plants suggest that the mammoth 

habitat in this region consisted ofan open 

coniferous/deciduous parkland. The geomorphic and 

stratigraphic context in the uplands around Lindsay has 

some similarities with localities to the southeast, at OTL 

Ridge (Figs. 2 and 12) and to the east, in the Pick City- 

Riverdale area (Fig. 2). At OTL (Fig. 12) similar upland 

eolian silts contain paleosols. The lowermost paleosols 

date to about the Pleistocene–Holocene boundary (Hill,

2003) and can be correlated to exposures ofthe Aggie 

Brown Member ofthe Oahe Formation around Pick 

City-Riverdale (Fig. 2) and other regional late- 

Pleistocene upland eolian–paleosol sequences (Artz, 

1995; Clayton et al., 1976; Rawling et al., 2003). 

Along the Yellowstone River (Fig. 2), Pleistocene 

fossils are found in gravel pits. Most of the pits are 

related to Pleistocene (fluvial) terraces. A pre-Wisconsinan 

(Sangamonian?/Illinoian?) faunal assemblage has 

been collected from the terrace gravels north of 

Miles City (Wilson and Hill, 2000, 2002; Hill, 1998) 

(Fig. 2). Besides Mammuthus columbi (Fig. 13) the 

faunal assemblage includes Megalonyx jeffersonii, 

Paramylodon ð¼ GlossotheriumÞ harlani, Mammut 

americanus, Equus, Arctodus simus, Camelops, and 

Bootherium ð¼ SymbosÞ. West ofMiles City, proboscidean 

(cf. Mammuthus) fossils have been collected from 

the Paragon gravel pit, while fossils referred to 

Bootherium ð¼ SymbosÞ have been found in gravels east 

ofthe town (McDonald and Ray, 1989). Several finds of 

Mammuthus have been reported from the gravel pits at 

Glendive (Fig. 2). At the Crisafulli pit, the gravels 

containing Mammuthus are overlain by silts (Fig. 14); 

this sequence forms the 12–15 m terrace along the 

Yellowstone River at Glendive (Hill, 2003). Collagen 

Fig. 13. Mammoth skull from Doeden gravels. 



Fig. 14. Mammoth-bearing Glendive gravels overlain by silts. 

from a mammoth tooth from the Glendive gravels 

provided an age of20,470780 14 C BP (Beta-155642) 

(Hill, 2003). Gravels deposited along Beaver Creek, a 

tributary ofthe Yellowstone River near Wibaux (Fig. 2) 

contain proboscidean remains (including fragments of 

tusks) that have been dated to 26,0007120 14 CBP 

(XAD-gelatin, SR-6086) (Hill, 2003). 

3. Geologic context 

3.1. Paludal– lacustrine, swamp-bog settings 

At the Merrell Locality (Fig. 2), swamp-bog and 

paludal–lacustrine deposits (designated as stratum B, 

Albanese et al., 1995; Hill, 1999b) contain mammoth 

remains. Radiocarbon dates associated with these 

sediments range in age from 442,000 to 32,000 14 CBP 

(Hill, 1999b; Table 2) (Figs. 15, 16). Thus the fauna 

from these deposits appears to date to the middle 

Wisconsinan (the pre-Last Glacial Maximum interstadial, 

isotope stage 3). 

In the vicinity ofthe Sun River, west ofAugusta 

(Fig. 7), Mammuthus remains are found in dark organicrich 

muds and clays. These swamp and paludal deposits 

date to about 11,500 14 CBP (Table 2) and are overlain 

by a 6 m thick sedimentary sequence chiefly formed of 

alluvium and colluvium (Fig. 17, 18). The sediments 

containing the mammoth fossils were deposited after the 

melting ofthe Sun River lobe Pinedale (Wisconsin 

Episode sensu lato) alpine-valley glacier. Remains of M. 

primigenius have been found in similar contexts east of 

the Upper Missouri Basin in late Wisconsinan pond 

sediments overlain by buried soils (Harington and 

Ashworth, 1986).

98 

3.2. Caves or rockshelters 

The major cave localities containing Pleistocene 

faunal remains are False Cougar Cave, Shield Trap 

Cave, and Natural Trap Cave in the Pryor Mountain- 

Fig. 15. Stratigraphic sequence at the Merrell Locality. 



Big Horn Mountain region (Fig. 2), and Blacktail 

Cave in the South Fork Dearborn River drainage 

(Fig. 7). False Cougar Cave contains late Wisconsinan 

faunal assemblages with dates of around 15,000 to 

10,500 14 CBP (Bonnichsen et al., 1986; Graham et al., 

1987; Table 2), while the Natural Trap Cave and 

Blacktail Cave faunal assemblages range in age from 

about 10,000 14 C BP to before the Last Glacial Maximum 

(Hill, 1996, 2000, 2001; Chomko and Gilbert, 

1987). Mammoth bone tools were recovered along with 

other Clovis artifacts from talus deposits possibly 

associated with a small collapsed rockshelter north of 

Livingstone (Fig. 2) (Lahren and Bonnichsen, 1974; 

Owsley and Hunt, 2001). The Clovis assemblage has 

been dated from about 11,500 to 10,500 14 CBP (Stafford, 

1999; Owsley and Hunt, 2001; Table 2). 

3.3. Alluvial deposits and fluvial terraces 

In the headwaters region ofthe Missouri River 

alluvial gravels, sands and silts at the Merrell Locality 

(Fig. 2) have been designated as stratum C (Albanese 

et al., 1995; Hill, 1999b) (Figs. 15, 16). Fragmentary 

remains of Mammuthus have been found in these 

deposits, which appear to be associated with the 

interstadial before the Last Glacial Maximum. Alluvial 

deposits containing Mammuthus fossils are known from 

Alder Gulch and the Gallatin Valley east ofDillon 

(Fig. 2), as well as the Helena area (Fig. 7) (e.g., 

Spokane Bar). 

Fig. 16. Chronologic interpretation ofthe stratigraphic sequence at the Merrell Locality.

Alluvial deposits within the Missouri River valley in 

the vicinity ofHavre (Fig. 2) have yielded Pleistocene 

fauna (Pecora et al., 1957; Fullerton and Colton, 1986). 

Alluvium overlain by the Havre till contains Mammuthus 

columbi, Equus exelsus, E. conversidens calobatus, 

and Camelops minidokae (identifications by C.B. 

Schultz, L.G. Tanner and C.S. Churcher in Fullerton 

and Colton, 1986). No published information is avail- 



Fig. 17. Sedimentologic context associated with mammoth remains in the glacial Lake Great Falls basin and Sun River area. 

Fig. 18. Stratigraphic, geomorphic, and chronologic summary ofmammoth-bearing deposits in the lower Yellowstone River Valley. 

able on what attributes were used to assign the 

Mammuthus remains to species level. The fauna may 

be Irvingtonian as the overlying Havre till has been 

assigned a pre-Illinoian age ofgreater than 546,000 BP 

(Fullerton and Colton, 1986). Along the Missouri River 

near Frazer remains of Mammuthus primigenius and 

Equus have been found in fluvial gravels overlain by till 

(ground moraine deposits) and sands and silts ofthe

100 

Kintyre Formation (Jensen and Varnes, 1964) (Fig. 2). 

The till and Kintyre Formation were assigned to the 

‘‘Tazwell’’, or possibly the ‘‘Cary’’ glacial advance 

(Jensen in Howard, 1960; both are within the Woodfordian 

and thus generally correlated with the late 

Wisconsin Episode, cf. Jensen and Varnes, 1964; Lemke 

et al., 1965; Fullerton and Colton, 1986; Karrow et al., 

2000). The underlying alluvial deposits were assigned to 

the Wiota gravels. The Wiota gravels at Tiger Butte near 

Frazer (Fig. 2) also contain Mammuthus (Jensen and 

Varnes, 1964). The Wiota gravels have been correlated 

with the Cartwright gravel (Howard, 1960) and the 

South Saskatchewan gravel (McConnell, 1886). 

Fluvial terrace gravels along the Yellowstone River 

contain Pleistocene fauna (Figs. 2, 18). The largest 

studied collection is from terrace sediments north of 

Miles City (Wilson and Hill, 2000, 2002). The faunal 

assemblage probably is Sangamonian or older, based on 

the geomorphic position ofthe terrace deposits. Samples 

from a Mammuthus columbi skull (Fig. 13) from this 

locality contain intact proteins potentially useful for 

phylogenetic studies (Hill and Schweitzer, 1999; 

Schweitzer et al., 2002). Other Pleistocene fauna likely 

to be associated with Yellowstone River terrace deposits 

include Bootherium ð¼ SymbosÞ collected from a gravel 

pit east ofMiles City (Payes collection, McDonald and 

Ray, 1989), and proboscidean (cf. Mammuthus) from 

the Paragon gravel pit west ofMiles City, as well as the 

BLM gravel pit at Miles City. Collagen of Mammuthus 

recovered from terrace gravels (ca. 12–15 m above the 

present river) beneath silts at Glendive has been 

radiocarbon dated to 20,470780 14 C BP (Beta-155642), 

providing a maximum age for the gravels (Figs. 14 and 

18). Other remains ofmammoth from Glendive have 

been assigned to Elephas ð¼ MammuthusÞ columbi (Hay, 

1914) (Figs. 19 and 20). 



Fig. 19. Stratigraphic context ofmammoth-bearing debris flow deposits (stratum D) at the Merrell Locality (see also Figs. 5 and 20). 

Deposits along the tributaries to the Yellowstone 

River in Montana also contain Pleistocene fossils 

(Winchell, 1882; Hay, 1924; Bass, 1932, Melton and 

Davis, 1999). In at least some instances these can be 

reliably attributed to alluvial contexts. For instance, a 

jaw from an immature mammoth was collected from a 

sand bar on Powder River, presumably redeposited 

from nearby alluvial sediments. The specimen is in the 

Range Riders Museum, in Miles City (Fig. 2). Another 

specimen referred to Elephas ð¼ MammuthusÞ columbi 

was reported from a sand bar along the Powder River 

(Hay, 1924). Mammoth teeth found in gravels about 

6–9 m above the present floodplain ofthe Tongue River 

(Fig. 2) (Bass, 1932) were identified as Elephas cf. 

E. columbi by J.W. Gidley (Bass, 1932). Other fossils 

recovered in a small arroyo, in gravel beds, and in the 

present floodplain ofthe Tongue River appear to have 

been redeposited from older sediments (Bass, 1932). Hay 

(1924) also reports remains of Elephas ð¼ MammuthusÞ 

columbi from along the Tongue River. Ungulate bones 

have been recovered from the ‘‘older alluvium’’ in the 

Tongue River basin (Heinrichs, 1988). Uranium-trend 

ages for paleosols within the alluvium range from 

around 100,000 to 30,000 BP and have been correlated 

with the Pleistocene Arvada and Ucross Formations and 

the Holocene Kaycee Formation (Leopold and Miller, 

1954; Fullerton in Heinrichs, 1988). Tusk fragments 

(proboscidea) have been collected from fluvial gravels 

along Beaver Creek in the vicinity ofWibaux (Hill, 

2003). 

3.4. Upland settings 

A nearly complete skeleton ofa Mammuthus columbi 

was recovered within upland silts underlying several 

buried soils near the divide separating the South Fork

Deer Creek drainage and Sevenmile Creek (designated 

the Lindsay mammoth in Wilson and Davis, 1994; see 

also Hill and Davis, 1998; Huber and Hill, 2003; Hill, 

2003). Radiocarbon ages of11,500780 14 C BP (Beta- 

102031) and 12,330750 14 C BP (SR-5576) appear to 

demonstrate that the silts containing the mammoth are 

possibly eolian deposits that can be correlated with the 

Aggie Brown Member ofthe Oahe Formation (Hill, 

2003). The overlying paleosols reflect intervals of 

stabilization which elsewhere have been related to 

moist-cool late Pleistocene and early Holocene climates, 

and increasingly arid middle Holocene (‘‘Altithermal’’) 

conditions (Rawling et al., 2003). The soils that formed 

under moist-cool climates may be the local equivalent of 

the regional Leonard Paleosol and Brady buried soil 

(Clayton et al., 1976; Reider, 1990; Kuehen, 1993; 

Albanese and Frison, 1995; Artz, 1995; Root, 2000; 



Fig. 20. Plan view showing spatial distribution of rocks and vertebrate remains from debris flow at the Merrell Locality. The left-hand side of the 

diagram shows location offaunal remains and rocks, while the right-hand side shows the bones with the rocks removed. 

William, 2000). This wetter-cooler climatic interval also 

may be locally present in upland stratigraphic sequences 

south ofGlendive (at OTL Ridge, Figs. 12 and 18). East 

ofthe Upper Missouri Basin, remains ofM. primigenius 

have been found in pond deposits under the Aggie 

Brown Member (Harington and Ashworth, 1986). 

4. Chronology of mammoth localities 

The chronological position ofsome deposits containing 

Pleistocene faunal assemblages from the Upper 

Missouri River Basin can be inferred using stratigraphic 

relationships and chronometric dating. Remains of 

Mammuthus, Equus, and Camelops occur in alluvium 

below pre-Illinoian till in the Milk River area (Fullerton 

and Colton, 1986). The Doeden gravels are possibly

102 

Illinoian or Sangamonian in age, based on K-Ar, Useries 

and radiocarbon dating ofregional stratigraphic 

sequences and geomorphic features. Based on radiocarbon 

ages, middle Wisconsinan (pre-Last Glacial 

Maximum) deposits are present at the Merrell locality 

and also in the lower deposits at Blacktail Cave and 

Natural Trap Cave (Table 2). The gravels containing 

Mammuthus and Equus along the Missouri south of 

Frazer are possibly middle Wisconsinan, ifthe overlying 

till is ‘‘Woodfordian’’ or late Wisconsinan in age. The 

mammoth recovered from Box Creek (south of Fort 

Peck) also dates to the interstadial before the Last 

Glacial Maximum (ca. 33,200 14 C BP). 

Faunal remains that can be attributed to the early 

part ofthe late Wisconsinan or Last Glacial Maximum 

(‘‘classic Woodfordian’’) include the assemblage from a 

debris flow at the Merrell locality (ca. 25,000– 

19,000 14 C BP, from Centennial Valley), the mammoth 

in the gravels at Glendive (ca. 20,500 14 C BP), the Lisk 

Creek bison (ca. 19,000 14 C BP), and fossils from 

Natural Trap Cave (Fig. 2). Localities containing faunas 

with radiocarbon ages indicating they are associated 

with the late Wisconsinan (Last Glacial Maximum to 

Younger Dryas) include False Cougar Cave, Blacktail 

Cave, the Sun River mammoth, the Deer Creek 

mammoth from near Lindsay, Indian Creek, Sheep 

Rock Springs, MacHaffie, the Colby mammoth, Mill 

Iron, Anzick and Shield Trap Cave. Extinct Rancholabrean 

elements are present in most ofthese later sites, 

although some ofthe localities contain some strata 

without time-diagnostic taxa. Age assignment thus may 

be based on relative stratigraphy, time-diagnostic faunal 

elements, geochronometric measurements (radiocarbon, 

luminescence) or a combination ofthese criteria. 

5. Summary and discussion 

Fossil vertebrate localities from the Upper Missouri 

Basin provide information on the paleobiotic character 

ofthe Rocky Mountains and western interior Plains 

primarily from the late Pleistocene (the Wisconsinan). 

Some fossils appear to date to the middle Pleistocene. 

The localities contain evidence for a variety of large 

extinct herbivores and some carnivores. The list of 

extinct animals includes mammoths, ground sloths 

(both Jefferson’s and Harlan’s), American mastodon, 

horse, camel, bison, muskox, dire wolf, American 

cheetah, scimitar cat, and giant short-faced bear. 

Smaller mammals have also been documented, from 

both cave and open-air settings. Faunas that have 

examined can usually be attributed to the Rancholabrean. 

Fossils probably dating to the Sangamonian or 

Illinoian have been collected from high terrace deposits 

along the Yellowstone River. Most ofthe localities with 

Pleistocene mammal remains are associated with the 



Rancholabrean; they are found in middle and late 

Wisconsin Episode stratigraphic and geomorphic contexts. 

The Upper Missouri Basin presently is characterized 

by a diverse set ofbiophysical contexts, ranging from 

wooded mountains to grassland plains and riparian 

settings. Geomorphic features and sedimentary sequences 

in the region are largely the product ofchanging 

environmental conditions in the Rocky Mountains and 

North American Great Plains during the Pleistocene. In 

particular, landscape evolution can be linked to changing 

climates associated with glacial and interglacial 

conditions. For example, the expansion ofthe southwest 

margin ofthe Laurentide Ice Sheet into the 

Missouri Basin is documented by the presence not 

only ofmoraine sediments (glacial till, diamictons) but 

also proglacial lacustrine, outwash, fluvial and eolian 

deposits. 

Besides the physical contexts, it may be useful to 

evaluate whether the available data, specifically the 

information from larger Pleistocene mammals, can be 

used to discern any biogeographic (spatial) or temporal 

ecological patterns associated with regional environmental 

change (glacial or interglacial conditions). 

Aspects ofthe Pleistocene mammal record in the Upper 

Missouri Basin can be used to infer the physical and 

biologic environments (habitats and biomes) over time 

within both glaciated and non-glaciated areas. The 

biotic patterns from the non-glaciated contexts of the 

Upper Missouri can be compared to the deglaciated 

areas within the drainage, as well as with adjacent icemargin 

and deglaciated contexts, for example the South 

Saskatchewan River area to the north, in southern 

Canada. 

Three fossil species of mammoth have been reported 

in the region. The most common identified species is 

Mammuthus columbi, while there are some potential 

examples of M. imperator and M. primigenius. Temporally, 

M. columbi appears to have been in the region 

from the middle Pleistocene (under the Havre till, and in 

possible Illinoian or Sangamonian gravels above the 

Yellowstone River at Doeden) through the end ofthe 

Wisconsinan. Within the Wisconsinan there are examples 

of M. columbi attributed to before the Last Glacial 

Maximum (Merrell, Box Creek) as well as the lateglacial 

interval (Sun River west ofAugusta, Deer Creek 

near Lindsay, Colby). A similar temporal pattern may 

exist in the glaciated region immediately adjacent to the 

Upper Missouri Basin in Alberta and Saskatchewan, 

Canada, where M. columbi has been reported from the 

interglacial Sangamonian or middle Wisconsinan age 

Echo Lake gravels at Fort Qu’ Appelle near Saskatoon, 

the pre-Illinoian (‘‘late Yarmouthian’’) and Sangamonian 

interglacial deposits at Medicine Hat, and the late 

Pleistocene (12,0007200 14 C BP, S-246) near Kyle 

(Harington and Shackleton, 1978; Stalker and Churcher,

1982; Wilson, 1996). The presence of M. columbi may 

be an indicator ofinterglacial conditions in glaciated 

regions, and non-glacial conditions (settings away from 

areas immediately affected by glaciers and their margins) 

during either glacial or interglacial times, and 

biomes possibly linked to grasslands with areas of 

shrubs, scattered trees and parklands. Mid-Wisconsinan 

(non-glacial) and late Wisconsinan (late- or post-glacial) 

radiocarbon ages on Mammuthus indicate a temporal 

gap associated with the Last Glacial Maximum in 

southern glaciated Alberta (Burns, 1996). 

Other proboscidean remains that can be tentatively 

identified to species level include the possible Mammuthus 

primigenius found at Tiger Butte, M. imperator 

fossils from Spokane Bar in the glacial Lake Great Falls 

area and along the Powder River, and Mammut 

americanum from the Doeden gravels above the Yellowstone 

River. The mammoth from Tiger Butte may date 

to before the last major glacial advance, and thus is 

likely older than Last Glacial Maximum. North ofthe 

Missouri Basin in the South Saskatchewan drainage, 

M. primigenius has been recovered in early and late 

Wisconsinan deposits at Medicine Hat, probable late 

Wisconsinan deposits at Chestermere Lake near Calgary, 

and sand and gravels forming a fluvial terrace at 

Empress (Harington and Shackleton, 1978; Stalker and 

Churcher, 1982; Wilson, 1996). The two potential 

examples of M. imperator from the intermountain 

setting associated with glacial Lake Great Falls and 

the plains setting ofthe Powder River can be compared 

to the presence of M. imperator in the late Wisconsinan 

deposits at Medicine Hat (Stalker and Churcher, 1982), 

and Empress (Wilson, 1996) (the Bindloss specimen, 

now identified as Mammuthus columbi, has a radiocarbon 

age ofabout 10,930 14 C BP, Hills and Harington, 

2003). Mammuthus primigenius and M. columbi may 

have been present in the North American Great Plains 

at the same time, with M. primigenius adapted to 

conditions associated with deglaciated tundra-like or 

transitional terrain and M. columbi present in nonglaciated, 

grassland and parkland landscapes or where 

more ‘‘interglacial’’ conditions prevailed. The one 

specimen that may be attributed to M. primigenius in 

the Upper Missouri Basin was found in glaciated 

terrain, and can perhaps be linked to colder conditions 

associated with tundra or tundra-boreal forest margins 

during the Wisconsinan. 

Ecologically, the possible presence of Mammuthus 

primigenius in the glaciated region at Tiger Butte may be 

an indication that open ground tundra or tundra-boreal 

forest margin conditions existed in the region prior to 

the Last Glacial Maximum, as has been inferred based 

on the Wisconsinan-age finds to the north from 

Chestermere Lake, Empress, and Medicine Hat (Harington 

and Shackleton, 1978). Remains of M. primigenius 

could imply localized tundra openings in steppe, 



parkland or forested areas, as indicated by fossils found 

in late Wisconsinan pond sediments or proglacial 

lake strandlines (cf. Harington and Ashworth, 1986). 

Warmer conditions possibly associated with interglacial 

conditions (either Sangamonian) or transitional glacial– 

interglacial conditions (at the end ofthe Pleistocene) 

may be indicated by M. columbi fossils from Merrell, 

Doeden, Box Creek, Sun River, Colby, and Deer Creek 

(Lindsay) in the Missouri Basin and Fort Qu ‘Appelle 

(Echo Lake Gravels), Medicine Hat, Bindloss, and Kyle 

to the north. In contrast to the tundra-like or tundraboreal 

forest margin habitats possibly implied by 

M. primigenius, the biotic landscapes associated with 

M. columbi may have been cool grasslands with scattered 

trees or parkland settings. Mammut americanum in 

the Doeden gravels could indicate pre-Wisconsinan 

age wooded settings along the Yellowstone River. 

The contexts associated with other larger mammal 

taxa may provide additional information on potential 

temporal and spatial patterns for the region. The 

presence ofwidespread areas containing some relatively 

open landscapes appears to be indicated by the presence 

of Equus, Bootherium/Symbos, Bison, Camelops, and 

Miracinonyx in both the intermountain areas and the 

plains. Ovibos is present in the same glaciated northern 

region that contains Mammuthus primigenius. Megalonyx 

and Paramylodon found at Doeden may be an 

indicator ofhabitats linked to Mammut. Thus, there is 

some fossil vertebrate data that may be suggestive of the 

presence oftundra-like or tundra-boreal forest margin 

in the area that was glaciated by the Laurentide Ice 

Sheet, wide-spread cool grasslands and parklands in the 

unglaciated plains and intermountain valleys, and 

wooded riparian settings, indicating a diverse array of 

habitats and biomes within the Pleistocene Upper 

Missouri River Basin. 

Acknowledgements 

I am especially grateful to John Storer for providing 

the opportunity to contribute this paper that is based on 

a presentation from the Third International Mammoth 

Conference in Dawson City, Yukon Territory. Tag 

Rittel kindly permitted the studies at Blacktail Cave, 

undertaken in collaboration with excavations directed 

by Les Davis and field supervised by Dave Batten. The 

fossils from the Doeden collection from Miles City were 

donated to Montana State University by Kathy 

Doeden. Mike Wilson provided valuable information 

connected with his studies ofthe Doeden local fauna. 

Information on and permission to study the mammoth 

teeth collected from the terrace gravels at Glendive was 

provided by F. Crisafulli. The Box Creek faunal 

assemblage was collected by Don Lofgren, Director of 

The Raymond M. AlfMuseum ofPaleontology.

104 

Investigations at the Merrell Locality were undertaken 

in cooperation with the U.S. Bureau ofLand Management, 

and collaboration in the field with Dave Batten 

and John Albanese. Dave Fullerton, Carol A. Edwards 

and Rufus Churcher provided information on vertebrates 

collected as part ofresearch associated with the 

United States Geological Survey. Fullerton and Churcher 

have been especially helpful in providing background 

information on their original research. Renewed field 

studies ofthe Lindsay mammoth were conducted in 

collaboration with Les Davis. Stratigraphic studies at 

OTL Ridge were conducted in conjunction with 

excavations by Les Davis. Funding for research was 

provided by a National Science Foundation MONTS 

award and the Kokopelli Archaeological Research Fund 

created by an endowment from Joseph and Ruth 

Cramer. Thanks to Richard Kuntzelman and Cheryl 

Hill for their fine work as research assistants and to 

Bruce Eng for drafting the figures. I am grateful to 

George (Rip) Rapp, Steven Holen, and H. Gregory 

McDonald for reviewing this paper and providing 

excellent suggestions that greatly improved its quality. 

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