Examination of the Owens Cache in Southeastern Colorado

Home , Clovis culture, Dent Site, Lamb Spring, Mano (stone)

EXAMINATION OF THE OWENS CACHE IN SOUTHEASTERN COLORADO

THADDEUS HARRISON SWAN

B.A., Fort Lewis College, 1999

A thesis submitted to the Graduate Faculty of the

University of Colorado Colorado Springs

in partial fulfillment of the

requirements for the degree of

Masters of Arts

Department of Geography and Environmental Studies

2019

THADDEUS HARRISON SWAN

This thesis for the Master of Arts degree by

Thaddeus Harrison Swan

has been approved for the

Department of Geography and Environmental Studies

Brandon Vogt, Chair

Thomas Huber

Stance Hurst

Date: May 8, 2019

Swan, Thaddeus Harrison (M.A., Applied Geography)

Examination of the Owens Cache in Southeastern Colorado

Thesis directed by Associate Professor Brandon Vogt

ABSTRACT

Throughout North America, caches are recognized as an important feature type in prehistoric research. Unlike other site or feature types, the materials associated with these assemblages are not a result of discard, breakage during manufacture, or accidental loss, but represent a rare window into prehistoric toolkits where usable items within various stages of manufacture are stored for future use. In addition, cache locations and the raw material source locations of the feature contents can assist with research questions regarding mobility and settlement/subsistence strategies (among others). However, many caches have been removed from their original context either through disturbance or discovery by non-archaeologists, who unwittingly destroy the context of the find. In other instances, archaeologists discover cache locations that are largely disturbed by erosion or lack the organic or temporal-cultural diagnostic artifact traits necessary for placement in a chronological framework, which greatly restricts the interpretive value of these assemblages. Therefore, when caches are discovered that retain contextual integrity, these resources are highly regarded for their information potential in prehistoric research.

First discovered in 2010, the Owens Cache (5LA12616) consists of a tightly clustered group of artifacts identified below a small bedrock ledge and crevice. Remnant portions of the crevice overhang exhibit depositional integrity where intact portions of the cache could feasibly be recovered. The fundamental goals of this thesis research are to perform test excavations of this feature in an attempt to reconstruct the depositional history and landscape features of the cache from a geomorphological perspective and provide a temporal framework for the assemblage. During the course of this investigation, a bisecting trench of the cache feature was

iii established with excavation terminating at bedrock. The results showed that an intact portion of the cache exists underneath one of the more prominent overhangs of the small bedrock shelf with three lithic tools identified within a solid depositional context. Through recovery of datable organics and an interpretation of landform stratigraphy, the feature could be reliably placed within the Protohistoric period and the geomorphic attributes of the landform defined.

ACKNOWLEDGEMENTS

I would like to express my sincere gratitude to Dr. Brandon Vogt, who provided patience, guidance, and support through the course of my graduate work, as well as the rest of my committee, Dr. Thomas Huber and Dr. Stance Hurst (Texas Tech University). All of who provided expertise and knowledge crucial to my research endeavors. I would also like to pay special attention to my father, Mark Swan, who provided help in many ways through the course of the field and laboratory work. I would have been hard pressed to accomplish my research goals without his tireless efforts and enthusiasm.

I am also grateful to Wayne Thomas and Jennifer Kolise of the Directorate of Public

Works, Environmental Division, Fort Carson, for their support in acquiring Archaeological

Resources Protection Act permissions and facilitating access to the Piñon Canyon Maneuver Site for the conduction of the fieldwork. As with many excavation projects, the fieldwork would not have been possible without volunteer help and my thanks goes out to Daniel Martinez, Bernard

Schriever, and Benjamin Zandarski II for providing several days of help in the field; as well as

Brian Brockman, Kendra Rodgers McGraw, Ryan Mills, Mark Owens, Kari Pittman, Glenn

Swan, Lynn Swan, and Erica Ward for devoting time when possible. Thanks to Dr. Vogt for committing his time and energy to provide a LiDAR digital scan of the cache. I would also like to thank Mark Owens and Roger Walkenhorst for their insights into developing the best possible methodology for this research.

I would also like to thank the University of Colorado Colorado Springs and the

Department of Geography and Environmental Studies, particularly Dr. Brandon Vogt, Dr.

Thomas Huber, and Monica Killebrew, for their support in providing access to the geomorphology lab and the use of the university total station for the fieldwork. A thanks also goes out to Julie Erickson and Stell for allowing me to utilize screens and other necessary field supplies.

An Alice Hamilton Scholarship through the Colorado Archaeological Society provided financial support for this research, which helped to fund processing of samples sent for specialized analysis, which was performed by Linda Scott-Cummings and PaleoResearch

Institute. While an Optically-Stimulated Luminescence sample was collected and ultimately not necessary to obtain a date for the assemblage, Dr. Amanda Keen-Zebert of Desert Research

Institute provided the equipment and expertise in order to collect this sample in preparation for a possible need. I am very grateful to these institutions for all of their support.

TABLE OF CONTENTS

CHAPTER I: INTRODUCTION ...... 1

CHAPTER II: PHYSICAL AND CULTURAL BACKGROUND ...... 5

PHYSIOGRAPHY AND GEOMORPHOLOGY OF THE PIÑON CANYON MANEUVER SITE .. 5

HYDROLOGY ...... 15

MODERN CLIMATE ...... 17

PALEOENVIROMENT/PALEOCLIMATE ...... 18

FLORA AND FAUNA ...... 26

CULTURAL OVERVIEW ...... 27

CACHING BEHAVIOR ...... 28

CULTURAL HISTORY OF THE ARKANSAS RIVER BASIN ...... 31

PALEOINDIAN STAGE (>11,500 TO 7,800 BP)...... 31

PRE-CLOVIS PERIOD (>11,500 BP) ...... 32

CLOVIS PERIOD (11,500 TO 10,950 BP) ...... 33

FOLSOM PERIOD (10,950 TO 10,250 BP) ...... 35

PLANO OR LATE PALEOINDIAN PERIOD (10,250 TO 7,800 BP) ...... 36

ARCHAIC STAGE (7,800 TO 1,850 BP) ...... 37

EARLY ARCHAIC PERIOD (7,800 TO 5,000 BP) ...... 37

MIDDLE ARCHAIC PERIOD (5,000 TO 3,000 BP) ...... 40

LATE ARCHAIC PERIOD (3,000 TO 1,850 BP) ...... 42

LATE PREHISTORIC STAGE (1,850 TO 225 BP) ...... 44

DEVELOPMENTAL PERIOD (1,850 TO 900 BP) ...... 45

DIVERSIFICATION PERIOD (900 TO 500 BP) ...... 46

PROTOHISTORIC PERIOD (500 TO 225 BP) ...... 49

CHAPTER III: METHODOLOGY AND DATA COLLECTION ...... 52

vii

INITIAL SURVEY AND LANDFORM ANALYSIS ...... 52

EXCAVATION PROCEDURES ...... 53

LABORATORY PROCEDURES ...... 56

ARTIFACT AND FAUNAL REMAIN ANALYSIS ...... 58

CHIPPED-STONE LITHIC ARTIFACT ANALYSIS ...... 58

CHAPTER IV: OWENS CACHE EXCAVATION RESULTS...... 62

OWENS CACHE LANDFORM ...... 62

SITE OVERVIEW ...... 65

CACHE EXCAVATION RESULTS ...... 68

DEPOSITIONAL HISTORY ...... 70

CARBONATE COATINGS AND OXIDATION ON ROCK FRAGMENTS ...... 84

CULTURAL MATERIALS FROM EXCAVATION ...... 86

FAUNAL REMAINS ...... 91

CHAPTER V: CONCLUSIONS ...... 94

REFERENCES CITED ...... 99

viii

LIST OF FIGURES

Figure 1.1. 2010 surface artifacts from cache (photo courtesy of Mark Owens) ...... 1 Figure 2.1. Geologic map of the Raton Basin-Sierra Grande Uplift Province (Higley 2007:4). Area denoted by pink boundary. Modified to show location of study area...... 6 Figure 2.2. Piñon Canyon Maneuver Site satellite imagery with key named landforms...... 7 Figure 2.3. Piñon Canyon Maneuver Site with landscape units as defined by Schuldenrein (1985)...... 8 Figure 2.4. Piñon Canyon Maneuver Site major soil complexes (Neve 1984)...... 11 Figure 4.1. Owens Cache site overview (crew at cache feature)...... 63 Figure 4.2. Slope profile of western Taylor Canyon, A-F designations denote slope positions with rock lithology attributes documented (see Table 4.1)...... 63 Figure 4.3. Owens Cache (5LA12616) site map...... 67 Figure 4.4. Overview of cache feature...... 68 Figure 4.5. Potential cache marker...... 69 Figure 4.6. Trench stratigraphy of cache at 5LA12616...... 71 Figure 4.7. North wall stratigraphy of Excavation Units 1, 2, and 7...... 72 Figure 4.8. LiDAR scan imagery of trench excavation and cache feature, contoured planview with black lines representing 10 cm intervals and gray 0.5 cm intervals...... 73 Figure 4.9. LiDAR scan imagery of trench excavation and cache feature, angled representation showing main cache area and northern trench side walls...... 73 Figure 4.10. LiDAR scan imagery of trench excavation and cache feature, close-up of main cache area...... 74 Figure 4.11. Planview map of cache feature showing artifact distributions and stone tool locations...... 76 Figure 4.12. Location of Field Specimen 127 in relation to the overhang...... 77 Figure 4.13. Biological soil crust remnants recovered from XU-2...... 78 Figure 4.14. .50 caliber bullet recovered during excavation...... 79 Figure 4.15. Field Specimen 158 location under overhang...... 81 Figure 4.16. Field Specimen 178 location under overhang...... 82 Figure 4.17. Cache planview showing stone tool locations in relation to overhang and bedrock exposures...... 82 Figure 4.18. Organic concretions identified under overhang (lower left concretion with rotted root fragment)...... 84

Figure 4.19. Rock fragments with carbonate coatings and calcrete recovered during excavation...... 85 Figure 4.20. Field Specimen 127 of the Owens Cache...... 88 Figure 4.21. Field Specimen 158 of the Owens Cache...... 88 Figure 4.22. Field Specimen 178 of the Owens Cache...... 89 Figure 4.23. Faunal remains recovered from excavation, (a) left mandible similar to Sceloporus sp. (fence lizard), (b) left mandible similar to Reithrodontomys sp. (harvest mouse), (c) unidentified bone fragment...... 92 Figure 4.24. Representative gastropods recovered from excavation, similar to known Central and Southern Plains specimens of (a) Family Succinidea (amber snail), (b) Pupoides sp. (cf. Pupoides abilabris [white-lipped dagger]), (c) Pupoides sp. (cf. Pupoides inornatus [Rocky Mountain dagger]), (d) Vallonia sp...... 93 Figure 5.1. Overview of Owens Cache landform post-excavation...... 96

LIST OF TABLES

Table 2.1. Cultural taxonomy of the Arkansas River Basin (Zier and Kalasz 1999)...... 32 Table 4.1. Rock fragment lithology, size, and roundness (see Figure 4.2 for slope position). .... 65 Table 4.2. Soil analysis data for trench stratigraphy (* denotes sediment under overhang)...... 72 Table 4.3. Summary data for recovered stone tools...... 87 Table 4.4. Debitage summary data for the Owens Cache...... 90

CHAPTER I

INTRODUCTION

In 2010, a small cache of stone artifacts, named the Owens Cache (5LA12616), was discovered at the Piñon Canyon Maneuver Site (PCMS) in southeastern Colorado (Owens

2015a). A cache as defined by Tunnel (1978:1) is “an accumulation of useful material that is hidden away for future recovery and utilization.” Comprised of large, broad biface-thinning flakes, blade-like flakes, and bifaces with overshot flaking (Figure 1.1), the Owens Cache tools exhibit a lithic technology rarely observed in southeastern Colorado assemblages and consist of readily identifiable exotic materials of Alibates agatized dolomite (primarily), commonly referred to as Alibates chert, along with Niobrara jasper. Given the assemblage location, concentrated

along the canyon slope immediately below a small

bedrock ledge/crevice, the potential for an intact portion

of the cache feature was considered highly plausible.

The importance of this potential is evident in the

literature, as cache locales are rarely identified with

suitable organics for temporal evaluation or many are

discovered by non-archaeologists, where these materials

are unknowingly removed from their original context

(Huckell and Kilby 2014; Hurst 2017, 2006; Kilby

2008; LaBelle 2015). In addition, diagnostic preform or

finished projectile point types like that found at the Post

Wallace Cache in Texas (Hurst 2017) or the Drake

Cache in northeastern Colorado (LaBelle 2015; Stanford

Figure 1.1. 2010 surface artifacts from cache (photo courtesy of Mark Owens).

1 and Jodry 1988) are rarely encountered such that they provide a temporal or possibly a cultural affiliation to these assemblages.

In the State of Colorado, a recent search through Office of Archaeology and Historic

Preservation (OAHP) records revealed a total of 37 locales that could be reasonably identified as caches based on site/feature descriptions (LaBelle 2015:3). While 11 caches were identified and subjected to controlled archaeological excavation, suitable organics for directly dating these features were only obtained for five (Cunnar and Chambellan 2014; Gilmore 2015; LaBelle 2015;

Metcalf and McDonald 2015). The remainder of the assemblages were compromised either by construction (landscaping, plowing, road work, etc.), were unwittingly taken out of context by their original discoverers, or were located on erosional landforms where little remained of the sediment matrix that presumably once preserved them. Although contextual information of these latter caches was partially or completely lost, three could be placed into a relative temporal framework by the direct association of diagnostic artifacts (Burns 1996; LaBelle 2015; Stanford and Jodry 1988; Westfall 2015). In the case of the Mahaffy Cache, Bamforth (2015) identified horse and camel protein residues along with the presence of distinct weathering rinds indicating considerable antiquity and a Late Pleistocene association. Three additional caches exhibited technological attributes and/or carbonate encrustations as a strong indicator of temporal or cultural affiliation (Basham and Holen 2006; Muñiz 2014; Patten 2015), with the remainder exhibiting characteristics that are more difficult to place within a chronological framework

(Adams and Johnen 2015; Black and Simons 2015; Eddy 1982; Gleichman and Becker 2015;

Johnston and Meeker 2015; LaBelle 2015; Pelton 2015; Perlmutter 2015; Troyer 2015).

Therefore, excluding the Owens Cache, 12 of the 36 known caches within Colorado can be tied to a temporal/cultural affiliation with more precise absolute dating acquired for only 14% of the known caches. However, LaBelle (2015:18) states there are still several other cache assemblages that await analysis in museums or in private collections.

2 While these undocumented caches certainly would contain information of varying significance depending upon the presence of diagnostics or perhaps remnant residues, the issue of context removal is consistently recognized. In the Southern Plains, where over 100 cache locations have been documented, this same matter is addressed (Hurst 2017:10). In addition,

Metcalf and Meeker (2015:115-116) ask why these cache assemblages have been so rarely identified, even within areas of extensive subsurface investigation like the Yampa Valley of northwestern Colorado, where patterns of “scheduled and anticipated reuse of [habitation] sites” are demonstrated. Two potential explanations proposed by the authors include: (1) strategic caching was so efficacious that few have been left unused or forgotten by prehistoric peoples and

(2) a concentration of stone tools has not been classified as a cache due to the disturbed nature of these finds in the present day. Therefore, when clustered assemblages show preservation levels to not only be recognizable as a cache feature, but are potentially in primary context; research of these locales is essential. These intact assemblages may not only provide a rare opportunity for establishing a temporal or cultural affiliation, but the artifact contents can provide a rare window into prehistoric toolkits and the presence of exotic materials can help to determine mobility and trade networks in a more comprehensive manner. Regarding the latter, the 12 Colorado caches with a temporal/cultural affiliation are of a broad time period of prehistory that spans from the early Paleoindian stage to the Late Prehistoric (Bamforth 2015; Cunnar and Chambellan 2014;

Gilmore 2015; LaBelle 2015; Metcalf and McDonald 2015; Muñiz 2014; Patten 2015; Stanford and Jodry 1988; Westfall 2015). Given this broad range of prehistory and the low sample size for each time period, establishing trends in temporal data for cache assemblages across the landscape would be difficult based on the current dataset.

The Owens Cache assemblage exhibits evidence of biface manufacture with overshot flaking, blade-like flakes, and broad biface-thinning flakes that have been compared to the Clovis technological tradition. However, overshot flaking and blade or blade-like flakes have been noted on sites confidently dated to a broader temporal period of prehistory (Basham and Holen

3 2006; Collins 1999; Cunnar and Chambellan 2014; Huckell and Kilby 2014; Muñiz 2014). The significance of the analytical research conducted by Collins (1999), Huckell (2014), and Muñiz

(2014) among others, is that important trends in morphology and size, curvature, and knapping strategies have been observed when compared to younger assemblages. These differences become very important in distinguishing temporal trends in cache assemblages where the artifacts have been removed from their original context and no remnants of these materials remain at the locale of discovery or the stratigraphic context cannot be interpreted based on the eyewitness accounts of the find (Huckell and Kilby 2014); especially when no diagnostic materials such as fluted Clovis points are directly associated with the cache. Another important aspect of lithic technology in reference to cache assemblages are that these materials do not represent items discarded or abandoned by prehistoric peoples; rather they consist of tools within multiple stages of reduction and retain enough utility to be stored for future use (Huckell and Kilby 2014:6).

While the main focus of this research on the Owens Cache is related to chronology and geomorphology, the potential of an intact component with a reliable absolute date could conceivably be used to expand upon or corroborate key technological differences between these temporal periods.

Considering the current state of cache research and the potential intact nature of the

Owens Cache, the primary purpose of this research is to investigate the cache from a geomorphological perspective in order to reconstruct the depositional history and landscape attributes of the feature area and provide a spatiotemporal framework for the assemblage. By accomplishing this objective, this cache feature may provide information to a growing prehistoric dataset, where temporal differences in artifact assemblages and landscape use can start to be elucidated.

4 CHAPTER II

PHYSICAL AND CULTURAL BACKGROUND

PHYSIOGRAPHY AND GEOMORPHOLOGY OF THE PIÑON CANYON MANEUVER SITE

The PCMS is a vast (952.97 km2) military installation located at the intersection of the

Colorado Piedmont, Raton Basin, and High Plains physiographic regions of southeastern

Colorado. While the PCMS is completely within the Raton Basin (Kuehn 2002:33; Trimble

1990), the geologic structures that define this physiographic region are located either on the northern boundary of the installation or a short distance to the east. According to Higley (2007:3-

4), the Raton Basin is defined by four geologic structures (Figure 2.1):

“(1) the western boundary is the Sangre de Cristo Mountains, the east flank of which is thrust faults that trend approximately parallel to the axes of the Raton Basin and Las Vegas subbasin; (2) part of the northern boundary is formed from the Wet Mountains and the Apishapa arch, a northwest-southeast extension of the Wet Mountains structure; (3) the southern boundary is defined by the Tucumcari Basin [or Las Vegas subbasin]; and (4) the eastern boundary is the [western] limit of the Sierra Grande uplift.”

While the Sierra Grande uplift is located a considerable distance to the south of the PCMS, the

Las Animas arch is a continuation of this geologic structure, which is orientated northeast/southwest and runs through southeastern Colorado to the east of the Purgatoire River

(Higley 2007:3). The Apishapa arch is exposed across the northeastern edge of the installation and is locally represented by the Black Hills uplift (von Guerard et al. 1987). The Raton Basin is a small depression (syncline) that contains sedimentary and volcanic intrusive rocks that generally date from the Cretaceous to the Oligocene or Miocene periods (Kuehn 2002:33; Smith

1975:78; Schuldenrein 1985:56). Primary volcanic intrusives of the Raton Basin are the Spanish

Peak stocks that include several radial dikes with additional extrusive lava flows visible throughout northeastern New Mexico and southeastern Colorado. Many of these basaltic flows can be observed along the upper elevations of the Raton Mesa and Mesa de Mayo landforms to the south of the PCMS, and one of the radial dikes comprises the southwestern boundary of the

5 military installation (Figure 2.2). These volcanic rock formations are thought to date between 25 and 22 million years (Smith 1975), however, the radial dike on the PCMS, locally known as the

“Hogback” follows a major Pliocene fault line leading Schuldenrein (1985:56) to conclude that the Hogback may be younger, forming between 7 to 5 million years ago.

Figure 2.1. Geologic map of the Raton Basin-Sierra Grande Uplift Province (Higley 2007:4). Area denoted by pink boundary. Modified to show location of study area.

Figure 2.2. Piñon Canyon Maneuver Site satellite imagery with key named landforms.

Schuldenrein (1985:2) identified four distinct landscape types on the PCMS. These include the Hogback, hills, steppes, and arroyo/canyon settings (Figure 2.3). The steppes are the open rolling plains that occupy the areas between the hills and the canyons to the southeast. All of the major canyon systems of the PCMS appear to be controlled by jointing patterns

(Schuldenrein 1985:62) and these drainages flow to the southeast and confluence with the

Purgatoire River at approximate 90-degree angles. In this region, areas of canyon sinuosity in drainage systems are believed to be the result of erosion of interbedded shale deposits and undercutting of the overlying resistant sandstone outcroppings. Canyon walls are primarily comprised of Dakota Sandstone with the lower drainage basin profiles containing sporadic exposures of the Morrison Formation. Within the Purgatoire River and the more deeply incised canyon mouths of Red Rock and Welsh, older sandstone, siltstone, and breccia outcrops of the

7 Bell Ranch Formation, Entrada, and Dockum Group are exposed. However, these Triassic to

Middle Jurassic age (Evanoff 1998) rocks only comprise a small portion of the PCMS study area.

Figure 2.3. Piñon Canyon Maneuver Site with landscape units as defined by Schuldenrein (1985).

Hill landscape settings on the PCMS include the Black, Big Arroyo, and Bear Springs

Hills. The Black Hills cover a horst-like uplift that is bounded on either side by a monocline.

Erosion of this landform has resulted in a stepped topography of a gently northeast dipping

Dakota Sandstone caprock and deeply incised northeastern flowing drainages. The deeper incisions of these drainages are exposing Morrison Formation Sandstones and Mudstones

(Schuldenrein 1985:55, 61). In contrast to the Black Hills, the Big Arroyo and Bear Springs Hills have primarily been formed by erosion of less resistant lithologies and are more accurately described as mesas. Both the Big Arroyo and Bear Springs Hills are heavily dissected by numerous ephemeral drainages. The eastern bases of these mesa landforms exhibit several headwater drainages, which eventually coalesce to form the deeply incised canyons of Taylor,

8 Lockwood, Red Rock, Stage, and Bent. Along the base of these mesas are numerous benches of more resistant Greenhorn Limestone outcrops with the scarps and caprock of the upper elevations exhibiting Carlile Shale and Fort Hays Limestone exposures. While these mesas are largely deflated or eroded landforms, Schuldenrein (1985:55-59) has documented the presence of sandy veneers and dune deposits within breaks of the limestone or along the base of the hills.

The upper steppes between the canyons and the mesas are highly erosional along the upper elevations with thick deposits observed in the ephemeral drainage systems. The primary formations overlying the Dakota Sandstone are Graneros Shale and the more resistant Thatcher

Limestone. Exposing Thatcher Limestone can be observed throughout the steppes and manifest as small benches or cuestas, of which the surrounding shale has been eroded. Areas of thick deposits characterize the steppes with accompanying large expanses of alluvium noted along all of the headwater drainages that dissect this area, along with some areas of aeolian and residual sediments in between.

Soils of the PCMS were originally described by Neve (1984) in a Las Animas County soil survey report conducted by the United States Soil Conservation Service. Neve (1984) identified four zones of closely associated soils on the PCMS that are largely based on similarities in underlying parent material and landscape characteristics (Figure 2.4). All of the soils are characterized as either shallow or deep with both being well drained. The soils are formed in aeolian sands, loess, residuum, alluvium, and colluvium and are primarily derived from shale, sandstone, and limestone. These soil groups include:

1. Penrose, Manzanola, and Midway Series

Members of these soil series types comprise the western half of the PCMS and include the

loessic plains along the extreme western boundary and the limestone-capped mesas and

cuestas. Both Penrose and Midway series soils are shallow entisols derived from limestone

and shale. Manzanola soils are deeper aridisols found on the open plains, in swales, and along

stream terraces.

9 2. Wiley and Kim Series

This soil group is localized to the southeastern corner of the PCMS and is generally deep and

well drained. Kim soils are defined as an entisol, typically formed from aeolian sands and silt

that occupy the steeper slopes of the plains. Wiley soils consist of a deeper aridisol that are

found on the gentler slopes and are characterized by thick Bt and Btk-horizons.

3. Travessilla, Wiley, and Villegreen Series

Travessilla soils comprise approximately 55% of the third group. Located along the eastern

side of the PCMS, the Travessilla series is found along the edges of the deeply incised canyons

and their adjacent gentle sloping plains. They are classified as a shallow entisol formed from

Dakota Sandstone residuum. Villegreen soils are very similar to the Wiley series aridisol,

however, the former develop closer to the edges of the canyons and are generally derived from

loess and sandstone residuum. These soils also exhibit shallower argillic B-horizons.

4. Gaynor Series and Ustolls

Located along the northern slopes of the Hogback, these soils consist of an ustic mollisol

(Ustoll) comprised of residuum and colluvium derived from the igneous basalt of the volcanic

intrusive. Gaynor series soils are classified as a shallow entisol derived from shale residuum

and these soils are found along the southern slopes of the Hogback.

Additional work by Schuldenrein (1985:101-201) also included the analysis of terrace and floodplain profiles and depositional histories of Van Bremer, Taylor, Lockwood, Red Rock, and Bent Canyons. Most of these cutbanks exhibited deep profiles with many sequences of aggradation and erosion along with (in general) weakly developed soil horizons observed. Based on radiocarbon dating of materials taken from several of these profiles, the sediments appear to primarily represent a time span between 4,500 and 1,100 years before present (BP). However, higher terraces along Van Bremer Arroyo and within Taylor Canyon exhibited characteristics that suggest possible association with a Late Pleistocene and Early Holocene temporal range.

10 Figure 2.4. Piñon Canyon Maneuver Site major soil complexes (Neve 1984).

A soil pit placed along a higher terrace of Van Bremer Arroyo exhibited a profile that contained a strongly developed argillic B-horizon with a significant level of calcium carbonate buildup. The lower boundary of the Btk-horizon exhibited larger clasts that contained 5 mm thick carbonate coatings on the undersides, which indicate soil development of a significant age.

Schuldenrein (1985:130) compared the level of pedogenic development observed in this soil pit to the Late Wisconsinan Broadway alluvium described by Scott (1963:37-39), which is a soil that marks the Pleistocene/Holocene transition and the period of extinction of Pleistocene megafaunal species. However, Scott describes Broadway alluvium to contain weak pedogenic development with a 3 ft thick AB-horizon and a lower C-horizon with calcium carbonate levels that only amount to sporadic streaks in the C-horizon matrix (Scott 1963:38). Scott also states that a soil in

Nevada that dates to the same temporal period also showed weak pedogenic development and that stronger development in Broadway alluvium may exist, but overlying Holocene soils that have

11 much stronger development may be masking the older Broadway soil development attributes.

Given these characteristics, the soil development observed by Schuldenrein is likely not tied to the Broadway series as delineated by Scott, but may either be a soil of the same age that was allowed to develop prior to burial or perhaps is of an older date range. In regards to the latter,

Scott (1963:35) describes a soil that developed at the upper boundary of the Louviers alluvium that contains a distinct argillic B-horizon with the level of calcium carbonate buildup that was noted in the Van Bremer soil pit. This soil type is thought to date to the Middle Wisconsin period or between 50,000 to 25,000 years ago, which likely predates human occupation of the region.

As such, further investigation is required to ascertain the true temporal periods of the upper terrace deposits within Van Bremer Arroyo. In any case, the soil Schuldenrein (1985) identified is of a significant age and likely date to the Early Holocene/Late Pleistocene or earlier.

In Taylor Canyon, near the main confluence with Big Water Arroyo, Schuldenrein

(1985:151) described a deep profile of a high terrace, of which the lowest stratum exhibited

“neutral colored mottles” with a radiocarbon date revealing an age of 8,470 ± 140 BP. This date indicates that remnant older deposits exist within this canyon system, of which portions are likely to have been eroded away during flooding events and dam breaches (see below).

In general, all of the canyon floodplains and lower terraces exhibited three cycles of significant deposition that are tentatively dated from 4,500 to 1,500 BP (Schuldenrein 1985:196).

The earliest of these deposits consisted of low energy alluvium that appears to be related to greater spring activity or a higher water table. Many deposits exhibited evidence of periods of standing water with iron stains observed on ped faces. The second cycle of deposition is comprised of general medium energy alluvium and the last cycle exhibits coarse bedload materials indicative of a higher energy, more significant period of aggradation. In Bent Canyon, the last period of deposition shows no evidence for subsequent soil development and appears to have occurred in a relatively recent time span. These three periods of aggradation are separated by intervals of soil stability (except the last cycle in Bent Canyon) and weak pedogenic

12 development or abrupt boundaries that indicate a period of erosion. Some of these erosional surfaces occurred on soils that exhibited calcium carbonate and clay accumulations that are indicative of a B-horizon, of which the overlying A-horizon was eroded away. When A-horizons were identified and a more intact paleosol was identified, the B-horizons exhibited calcium carbonate development and clay illuviation (in most cases) indicative of an aridisol (Schuldenrein

1985).

While these three major cycles of deposition generally correspond with the pre-Piney

Creek, Piney Creek, and post-Piney Creek alluvial sequences proposed by Scott (1963),

Schuldenrein (1985:201) notes one significant difference in comparison to the PCMS profiles.

Although discrete terraces generally define the various Piney Creek sequences, the soil profiles of the PCMS are continuous with each depositional sequence showing pedogenic alteration followed by burial from the ensuing depositional cycle. Schuldenrein (1985) also argues that these three depositional sequences are more indicative of stratigraphic profiles studied in the Southwest. At

Chaco Canyon, Hall (1977) observed aggradational phases between 4,100 BP and 2,400 BP and between 2,000 BP and 850 BP, which closely matches the first two cycles of deposition noted in the PCMS profiles. According to Schuldenrein (1985), further study is needed to confirm the possible relationships to these other depositional sequences. The general lack of deposits prior to

4,500 BP may relate to a period of significant erosion following the Altithermal climatic episode

(Schuldenrein 1985).

Two of the canyons (Taylor and Bent) contain unique characteristics and require further description. Taylor Canyon exhibits high cliff faces and a narrow stream channel. Sediment deposits within this canyon show a slightly different depositional sequence as mass wasting of the cliff sides has led to damming of the drainage and created numerous areas of ponding for significant periods of time (which is still observed today). In addition, the stratigraphic profiles show periods of significant sediment aggradation, where it appears the dam systems were overwhelmed and breached. As such, many reaches of Taylor Canyon exhibit complex cut and

13 fill sequences followed by periods of slow accretion in relation to a ponded or marsh environment.

Bent Canyon is one of the shortest drainages on the PCMS and it exhibits the highest total slope and the greatest stream sinuosity in comparison to the other canyons. While this has created areas of significant erosion, there are also areas of the canyon that have acted as sediment traps and some of the best-developed soil profiles of the PCMS were seen in these areas.

Therefore, Bent Canyon holds the greatest potential for the long-term preservation of intact archaeological deposits (Schuldenrein 1985).

As a follow-up to the work of Schuldenrein (1985), McFaul and Reider (1990) examined eolian dune deposits along the headwaters of Taylor Arroyo and along the western PCMS boundary as well as alluvial stratigraphic sequences within Bent and Stage Canyons. The McFaul and Reider (1990) investigation provided sound evidence that the eolian sands and higher terraces exhibited stratigraphic sequences of Pleistocene and Early Holocene age, as well as Middle to

Late Holocene deposits of varying soil development attributes. Within the Bent and Stage

Canyon terrace deposits, the upper T2 terrace of Bent and deep cutbanks within Stage showed buried paleosols with B-horizons exhibiting substantial clay illuviation, carbonate accumulations, and in the case of Stage Canyon, secondary carbonate buildup. The Bent Canyon T2 terrace

(named the Coder terrace) contained two paleosols, the lowest of which exhibited Stage II+ calcium carbonate development (Bkb-horizon) potentially dating to earlier than 8,000 BP.

Radiocarbon dating of the lowest paleosols in Stage Canyon revealed A-horizon organics dating to 12,990 BP and 11,030 BP or within the Late Pleistocene and Early Holocene transition. These dated components were buried at 5.7 m and 3.7 m below the modern ground surface respectively, with additional buried horizons that consisted of highly developed mollic epipedons with Btb- horizons or minimally developed entisols in the highest portion of the stratigraphic sequence.

These likely date from the Middle to Late Holocene. Stripping and truncation of some of these well-developed soils with secondary calcium carbonate accumulation in both the A and B-

14 horizons indicate fluctuation between mesic and xeric climatic conditions (McFaul and Reider

1990:III-9 – III-18).

Investigation of the eolian sands both along the western edge of the installation and within the dune deposits along the base of Dillingham Ridge and along the headwaters of Taylor

Arroyo also revealed evidence of older soils likely dating from the Pleistocene to Middle

Holocene or Altithermal climatic period. While no radiocarbon dating was accomplished at these locales, the presence of well-developed argillic B-horizons with additional accumulations of

Stage II calcium carbonates indicate a substantial age for these deposits. Work by Gile (1975) in the Southwest has shown that carbonates inhibit clay illuviation with the Bt-horizon alone likely being formed prior to carbonate accumulation, which effectively halts or slows down clay movement into the B-horizon matrix (McFaul and Reider 1990:III-3).

Based on the investigations conducted by Schuldenrein (1985) and McFaul and Reider

(1990), the soils of the PCMS are indicative of a broad timespan of prehistory with potential paleosols identified that date from the Late Pleistocene to potentially only a few hundred years ago, within the Protohistoric period. However, it should be commented, that the likelihood for cultural site preservation would vary depending on the energy level of aggradation during alluvial events and the extent of erosion that has stripped some of the paleosol units (McFaul and Reider

1990:III-26 – III-29).

HYDROLOGY

The study area lies within the Arkansas River basin with the Purgatoire River marking the eastern boundary of the PCMS and represents a major tributary to the Arkansas. The headwaters of the Purgatoire originate in the Sangre de Cristo Mountains to the west of Trinidad,

Colorado, with drainage confluence forming the primary channel along the Pete Hills. Along the middle reach of this river, the canyon is deeply incised with exposures of Triassic, Jurassic, and

Cretaceous rock observed. The floodplain in this area is as great as 1,800 m wide, of which the

15 numerous side canyons in the Picketwire Canyonlands to the east and the numerous southeastern flowing canyons of the PCMS likely helped to create. Work by Dean and Schmidt (2013) along the Rio Grande River has shown a considerable widening of the river in those areas where multiple stream channel confluences are observed. However, Schuldenrein (1985:90) documented evidence of basalt-veneered benches in the area of the Taylor Canyon confluence, which Schuldenrein described as “cols” and appear to represent surfaces formed from glacial outwash. In addition, McFaul and Reider (1990:III-20) identified loose rounded to sub-rounded gravels on a terrace 18 m above the floodplain. These gravels were of quartzite, granite, and volcanic lithology of the Rocky Mountains and contain attributes strongly indicative of a

Pleistocene age. Therefore, it is likely that both glacial flooding and multiple side canyons have created the large valley of the Purgatoire Canyon, which is the most prominent landform in this region.

The side canyons of the PCMS are ephemeral and in the absence of the summer to early fall North American Monsoon (NAM) rains, are usually dry with rainfall and stream flow studies documenting very little to no flow from the water table. Based on these studies, an average precipitation event of one-inch is necessary to produce stream flow in the arroyos with accompanying sediment yields (Stevens et al. 2008). In most instances, von Guerard et al. (1987) found the water table to exist “tens of meters” below the modern ground surface. With the exception of the NAM season, the main source of water is the Dakota-Purgatoire Aquifer, in which water collects within fractures and voids within the Dakota Sandstone bedrock. This can manifest as springs within the canyons where interbedded shales exist and groundwater sapping weathering processes are observed (Laity and Malin 1985). Evidence of mass wasting and natural damming within Taylor Canyon have created several areas of pooling, which even in xeric conditions contain water.

Historically hand-dug or drilled wells into the aquifer were the primary source of water with springs along the canyon settings providing some surface water pooling. According to von

16 Guerard et al. (1987) these wells could produce between 10 to 500 gallons per minute.

Prehistorically, there is evidence from soil studies of more mesic conditions in the upper headwaters of Taylor and Lockwood where cienaga-like alluvial fills have been documented, which indicates increased spring activity. The presence of thick mollic epipedons along with areas of gley soils further support moist climatic conditions during some periods of prehistory where reliable water sources were more readily available across the landscape (McFaul and

Reider 1990).

MODERN CLIMATE

Due to the high elevation of the Colorado Plains, the leeward geographic position in relation to the Rocky Mountains, and the mid-latitude continental interior location of the PCMS, this region is characterized as semi-arid with the potential for drastic seasonal variations

(Mahoney et al. 2015). The dominant westerly winds bring storm systems from the Pacific

Ocean, which typically loose much of their moisture over the higher mountains, leaving the plains with little effective precipitation, especially during mid-winter (Doesken et al. 2003). During the monsoon season of mid-July to September, there is a shift in the wind patterns, which brings moisture from the Gulf of California. The vast majority of the precipitation falls onto the

Colorado Plains during this time with localized heavy rains often resulting in widespread flooding. Heavy snowfall within the region is sometimes referred to as an “upslope storm” where cold air masses from the north interact with moist air coming from the south. As these cold air masses are often too low in elevation to cross the mountains, extreme blizzard conditions along the plains are frequently the result (Doesken et al. 2003). The study area receives an average of

12 inches of precipitation a year (von Guerard et al. 1987).

The thin atmosphere at this elevation (1,311 to 1,768 m [4,300 to 5,800 ft] at the PCMS) results in greater penetration of solar radiation, generally creating warmer near-surface conditions. Colder temperatures are typically due to air masses arriving from the north, of which

17 there is little moisture associated, unless it collides with southern air masses. When the plains are covered by low lying cold air masses, warm westerly Chinook winds can develop off of the mountains that cause drastic and sudden shifts in temperature. However, these winds usually do not cause as drastic a change because of the area’s vast distance from the foothills of the Rocky

Mountains (Doesken et al. 2003).

The most consistent weather data close to the PCMS originate from the Perry Stokes

Airport, which lies 24 km (15 miles) from the western study area boundary. Data collected at this station is from 1948 to the present with snow accumulations only documented from 1948 to 2001

(Doesken et al. 2003). Based on this dataset, the average annual high temperature is 19.7° C

(67.5° F) with an average low of 2.7° C (36.8°F). The highest temperature is typically in July with a range average of 28.5° C (83.3° F) to 35.1° C (95.2°F). The highest average temperature of 35.1° C was recorded in July 2003 with the lower average temperature (28.5° C) recorded in

July 1950. In the winter months, December to February exhibit the coldest temperatures with a range average of -14.4° C (6.1° F) to -6.9° C (19.6° F). The lowest of these was recorded in

January 1963 with the higher value documented in December of 2014. Average precipitation for these years is 12.9 inches with the highest total being in 1979 at 20.76 inches and the lowest being 5 inches in 2012. From 1948 to 2001, the average snowfall was 40 inches with 1990 exhibiting the most snow at 74.2 inches and only 11.4 inches fell in 1950.

PALEOENVIROMENT/PALEOCLIMATE

The eastern plains of Colorado during the Last Glacial Maximum (LGM) from 17,850 to

14,500 BP are marked by a very cold and dry climate. Climate studies indicate that the maximum glacial extent of the Colorado mountain glaciers were also accompanied by a 44% precipitation drop compared to modern values (Brunswig 1992:7). According to Brunswig (1992), the

Colorado Front Range exhibited significant vegetation zone differences compared to the present.

During this time, alpine tree lines were depressed at least 488 m (1,600 ft) and alpine life zones

18 may have been as low as 1,524 to 1,829 m (5,000 to 6,000 ft) in elevation, which corresponds to the lower foothills of the Rockies. The eastern plains of Colorado consisted of cold expanses of open shortgrass species with the drainage basins containing sporadic stands of riparian spruce- pine woodlands. The faunal assemblages within these dated deposits have contained sparse numbers of camel, horse, and rabbit specimens. Therefore, all indications are that this period is marked by a fairly low carrying capacity with mammoth remains nearly absent from these contexts (Brunswig 1992).

Following the LGM, the Bølling-Allerød warm period began and this climate shift has been documented by Greenland ice core samples along with other North American and European climate studies (Dunbar 2006a; Yu and Eicher 2001). This shift began at approximately 14,500

BP and is documented to have lasted until 11,000 BP, at the beginning of the Younger Dryas climatic reversal. This general warming and more mesic time period is separated by the Older

Dryas, which is not included in some climate change temporal diagrams due to the short time span of this episode and the lower resolution of previous climate studies, which have not shown this period of change to exist. However, the high-resolution study performed by Yu and Eicher

(2001:3) not only revealed evidence of the Older Dryas, but also showed evidence of smaller climatic oscillations during the Bølling-Allerød period. Similar to the Younger Dryas, the Older

Dryas and these other smaller climatic oscillations are a reflection of shifts to colder environmental conditions. Glacial retreat during these periods has been shown to have either stopped or re-advanced (Dunbar 2006a). These changes are believed to be due to vast quantities of non-saline meltwater reaching the North Atlantic or Gulf of Mexico, which effectively shifted the current of the Gulf or North Atlantic Streams and resulted in a significant change in climate that is believed to be comparable to previous Ice Age conditions (Dunbar 2006a:121). Both

Dunbar (2006a) and Broecker (2006) have suggested that these climate reversals could have been triggered by some of the major glacial outburst floods that occurred during this long deglaciation period.

19 The Bølling-Allerød period corresponds with the possible presence of Pre-Clovis cultural groups and the initial identification of Clovis at ca. 11,500 BP. Prior to the known Clovis occupation of the Colorado region, the paleoenvironment of Colorado was described by Brunswig

(1992:8-9) as a warmer climate with precipitation rates that averaged 10-25% greater than the present day, which is a significant increase compared to the LGM. Seasonal variation was also not as noticeable, which led to less evapotranspiration and effectively created a much more humid environment. Faunal assemblages show significant increases in bison, mammoth, camel, horse, ground sloth, and llama during this time frame and some have suggested that the mammoth populations of Colorado were at its highest levels during this time and the subsequent Clovis period. During later Clovis times, the generally warm and moist climatic conditions persisted in

Colorado and the vegetation community consisted of mixed tall and shortgrass savannahs and large patches of spruce-pine woodlands throughout the modern day Colorado Piedmont region.

The upper mountain tree lines would have only been depressed by about 305 m (1,000 ft) compared to modern day conditions and the foothills would have contained much denser woodland communities. The identification of humic gley soils at many Clovis sites, which would have formed during periods of persistent high water tables, further attests to the mesic environment of this temporal period (Brunswig 1992).

Stratigraphic studies at the PCMS may support the climatic oscillations during this time frame. McFaul and Reider (1990:III-24) identified thin alluvial deposits within the Stage Canyon cutbank with a radiocarbon date of approximately 13,000 BP. In this sequence, weak, reworked

A-horizons were observed with relatively minimal aggradation and several shifts from coarse to fine clast sizes. This indicates that this area experienced short-term episodes of stability with the low alluvial aggradation and changing depositional attributes potentially representing climatic fluctuation.

The Younger Dryas climatic period is dated from 11,000 to 10,000 BP and corresponds with the appearance of Folsom, the extinction of Pleistocene megafauna, and an overall lack of

20 Clovis sites in the archaeological record. Regarding the latter, some have questioned whether this climate shift is related to the overall lack of evidence for this cultural complex (LaBelle 2012).

Brunswig (1992:12) states that an early drought tied to this period, which may have started as early as 11,300 BP in Colorado, likely drove large megafaunal species, especially mammoth, out of the region and as a result of this subsistence base loss, Clovis populations may have been reduced and/or became more focused towards bison hunting. A reliance on bison, even in the earlier times of the Clovis period, is certainly demonstrated at such bison kill sites such as Jake

Bluff, Aubrey, Blackwater Draw, and Murray Springs (Holen 2014:179). Ballenger (2015) has argued that the large percentage of mammoth fossils and Clovis kill sites within the San Pedro

Basin of Arizona, may indicate that this area was a refuge for terminal Pleistocene mammoth populations given the evidence of large watering holes. Unfortunately for the mammoths, this account would also mean that mammoths were concentrated in a more localized area, which could have been taken advantage of by Clovis hunters. Based on the number of mammoth kill sites identified in the basin, there is good evidence that Clovis people did make good use of this opportunity. Holen (2014:78) also states that the remnant playas of northeastern Colorado may have also been a mammoth refuge and many of these playas contain evidence of Clovis occupation.

Research into Younger Dryas hunter-gatherer populations worldwide has shown that, overall, the environmental changes of this period did not heavily affect human societies, as very little change in cultural assemblages or practices were noted during this transitional period

(Meltzer and Bar-Yosef 2012). In addition, Meltzer and Bar-Yosef (2012:251) argue that the evidence for climate change varies too much from region to region with only slow changes in climate observed to have made a significant impact on human populations. The one exception to this line of thought is the cultural change observed in the American West, with the transition of

Clovis to Folsom apparent in the archaeological record (LaBelle 2012). Meltzer and Bar-Yosef agreed with LaBelle that while the timing of this cultural shift may indicate an environmental

21 cause, many other cultural factors could have played a part in this transition. However, given the megafaunal extinctions that took place in North America, which occurred at the same time as the

Clovis/Folsom transition, it seems likely that the shifting climate did play some role in the changes observed to both the paleontological and archaeological records.

Meltzer and Bar-Yosef (2012:251) also state that some areas of the United States exhibited cool and dry climates, while other regions were either cool and humid or even warm and humid during this time. This variability should be expected across such a broad geographic area, however, the overall trends of the Younger Dryas climatic reversal are documented in many areas of the northern hemisphere and certain regions were certainly impacted more than others.

Dunbar (2006a:112, 121) argues that the differences in climate across the United States can be explained by the geographic location of the influx of glacial meltwater. When the Gulf of

Mexico contained lower percentages of glacial meltwater, the Bermuda High pressure zone shifted to the east, which produced a significant wet cycle in the southeastern United States, while the western coast experienced more arid conditions. The opposite occurred when glacial meltwater was in higher percentages in the Gulf of Mexico compared to the North Atlantic and the eastern United States exhibited increased drought.

Brunswig (1992:12-14) describes the paleoenvironment of eastern Colorado during the

Younger Dryas interval as a warming and drying period, which is at odds with the paleoenvironmental data collected at the Bull Creek site in the Oklahoma Panhandle (Bement et al. 2006), which clearly documented a significant cooling period during this same timeframe.

While this may be due to regional differences, the close proximity of these two locales may indicate significant oscillations in climatic conditions or possibly more accurate proxy data from

Bull Creek. The overall vegetation communities in Colorado at this time include increased areas of semi-arid shortgrass prairie and the eastern movement of the mixed tallgrass and shortgrass savannah environments. While some stands of spruce-pine woodlands are still present along the major river basins, the majority of these riparian species now consist of deciduous trees such as

22 cottonwood. Large megafaunal bison species are still found in faunal assemblages of this time period, as was some evidence of lingering populations of camel. However, all other megafaunal species are absent from the record and appear to have gone extinct at this time. During this time,

Folsom kill sites show a heavier reliance on bison for their subsistence needs.

At the PCMS, research along Stage Canyon revealed evidence of a thick mollic epipedon with a significant rate of alluviation associated. The A-horizon of this mollisol was dated to

11,030 BP and McFaul and Reider (1990:III-25) suggest that this sequence indicates a long climatic period of moist conditions that appears to have persisted until approximately 8,500 BP with the Altithermal beginning shortly thereafter. Whether these data are shown to be consistently represented across the PCMS and the larger region, the study area may be located far enough to the south to have been largely unaffected by the Younger Dryas climatic reversal, which has been shown to be absent or barely recognizable in more southern environments

(Borrero 2012, Dillehay 2012, Meltzer and Bar-Yosef 2012).

After 10,250 BP, Folsom sites start to be replaced by Plano period cultural groups. This period is classified by a proliferation of different projectile point types and evidence for cultural regionalization and population density increases through much of North America. The Plano period is dated from 10,250 to 7,800 BP and the general climate in Colorado is described as a time of increasing annual temperatures and decreased precipitation along with growing seasonality differences. By the middle of the Plano period, the overall climate appears to mirror modern day conditions (Brunswig 1992:16). Shortgrass and sagebrush/yucca prairies continue to grow and replace remnant stands of woodland that are not connected with the large drainage basins, such as the Arkansas or the South Platte Rivers. Tallgrass species continue to migrate east and are only found in sparse patches across the eastern boundary of the Colorado Piedmont. The open grasslands are prime habitat for bison and their populations appear to be increasing exponentially during this period. This is reflected in the large bison kill sites that are found throughout the plains during the Plano period. However, with data obtained by McFaul and

23 Reider (1990) (as discussed previously), there is evidence for a long period of mesic conditions through much of this time period and southeastern Colorado may have had more significant precipitation amounts than is reported by Brunswig.

By the end of the Plano period (ca. 7,800 BP), the Colorado eastern plains and the greater central plains region exhibits increased hot and dry climatic episodes that were only ameliorated by brief stints of slightly colder and wetter periods, but overall these conditions were well below modern levels. This climate shift marks the beginning of the Altithermal period, which is accompanied by a large reduction of archaeological sites throughout the High Plains. Some researchers have suggested that the plains were nearly abandoned during this period with refuge found in the higher mountains of the Colorado Rockies (Benedict and Olsen 1978; Brunswig

1992; Reeves 1973).

At the PCMS, there is evidence of terrace abandonment as well as erosional events that removed portions of the underlying paleosols. Along with secondary carbonate accumulations within the A and B-horizons of these paleosols, there is a clear indication of a shift to arid conditions comparable to that reported for the Altithermal period (McFaul and Reider 1990:III-

25). The loss of Late Pleistocene to Early Holocene soils within the floodplains of many of the canyons and along the higher steppes has also been attributed to this event (Schuldenrein 1985).

These data certainly suggest that little deposition along the floodplains and in the region in general occurred through this period and supports the idea that Early Archaic populations did not necessarily abandon the plains, but there is a paucity of site preservation due to widespread erosion.

At the end of the Altithermal and within the Middle Archaic period (5,000 to 3,000 BP), there is ample evidence of a substantial climate shift towards cooler and moister conditions. At this time, McDonald (1992) notes an expansion of grassland and riparian ecosystems with geomorphological data at the PCMS exhibiting attributes that indicate a return to more mesic conditions. While not associated with radiometric data, McFaul and Reider (1990) note the

24 development of two mollisols above the unconformity caused by the Altithermal period. The lowest of which exhibits a 40 cm thick A-horizon that formed for a lengthy period under moist conditions. Similarly, Schuldenrein (1985:225) documented sediments within this timeframe to contain ponded clays and silts indicative of a higher water table. During the Middle Archaic there is a drastic increase in site numbers and if these sites do reflect population dynamics, a correspondingly expanded population base. These apparent changes to the environmental conditions likely played a key role in this transition.

Subsequently, within the Late Archaic period (3,000 to 1,850 BP) and the Late

Prehistoric stage (1,850 to 225 BP), pollen records and geomorphological data point to several periods of climatic fluctuation with primarily arid conditions observed, but being interrupted by brief periods of stability and more mesic conditions (McFaul and Reider 1990; Scott 1984; Scott-

Cummings and Moutoux 2001; Schuldenrein 1985). Within soil profiles, this is primarily seen with erosion of the lower well-developed paleosols and overlying sequences of poorly developed

A/C horizons along with inter-fingering or capping colluvial deposits. In this timeframe, notable periods of drought with intervening spells of increased moisture were observed. Based on pollen data from excavations at both the Sue Site (Scott 1984) and within Welsh Canyon (Scott-

Cummings and Moutoux 1991), drought conditions were implied to exist with the associated strata radiocarbon dated from 900 to 780 BP. However, by 750 BP (or Anno Domini [AD] 1200) these data show a return to more mesic conditions with a cooler and wetter climate. This would appear to be in contrast to the extreme drought conditions reported for the overall Central Great

Plains region (Bryson et al. 1970). However, Scott (1984) pointed out “the same westerlies that result in decreased precipitation in the prairie peninsula would generate increased precipitation in southeastern Colorado and the panhandles of Oklahoma and Texas (Bryson et al. 1970)”.

By 700 BP, there appears to have been a short-lived period of more xeric conditions with a sudden shift back to a cooler and moisture climate that culminated with the development of the

25 Little Ice Age (Scott 1984:22), which ended in AD 1860. Climatic conditions have since ameliorated to that of the present day.

FLORA AND FAUNA

The PCMS is comprised of a range of ecosystems that include grasslands, pinyon pine- juniper woodlands, semi-desert shrublands, and riparian. In a study of these primary vegetation zones, Shaw et al. (1989) described 26 plant communities on the installation that are based on the primary species comprising each, which are largely dictated by the types of soil and underlying parent lithology that helps to support the variety of vegetation observed. Grasslands are the largest ecosystem, comprising approximately 65% of the total area. Various portions of the grasslands are dominated by shortgrass species of blue grama, western wheatgrass and galleta, with the addition of tree cholla or broom snakeweed noted in some of these communities. Many of these areas are also comprised of dense patches of common sunflower, Russian thistle, or downy brome (cheatgrass), the latter of which are considered invasive. Sparse areas of tallgrass species, such as little bluestem or sand bluestem, can also be found.

Typical shrubland communities are composed of either dwarf species, such as Bigelow’s sage, frankbush, or greasebush; or larger sized species of fourwing saltbush, rabbitbush, or sand sagebrush. These plants are usually comprised of various densities with bunchgrass understories dispersed throughout. Woodland ecosystems are either noted within the hills or along the edges and within the canyon settings. While one-seed juniper dominates most of these environments, pinyon pine is common and sparse stands of Ponderosa pine have also been observed. Larger shrub species of skunkbush sumac and true mountain mahogany are also noted in this environment. Within wetter areas of the canyon and arroyo systems, riparian ecosystem patches exist. Cottonwoods tend to dominate these settings with willow, rushes, horsetails, cattails, and sedges (among others) commonly found in association (Hazlett 2004; Milchunas et al. 1999).

Within Spring Canyon (to the north of Taylor) a small growth of aspen trees have been observed.

26 Economically important plant species to historic or prehistoric peoples have been documented as chenopodium (goosefoots), pigweed, juniper, pinyon pine, beeweed, buffaloberry, mustard family, prickly pear, cholla, Indian ricegrass, mint family, sagebrush, skunkbush, carrot family, cattail, globe mallow, chokecherry, legume family, purslane, and sunflower (Scott 1984).

The importance of goosefoots to prehistoric peoples appears to be high with large percentages of charred seeds found in many site contexts (e.g. Puseman et al. 2008; Scott 1984).

The diverse ecosystems of the PCMS are home to a variety of native fauna, as well as migratory bird species. Historically and prehistorically important species consist of animals that provided food, fur for trade, were culturally revered, or were threats to the livelihood of the people. Any list of these important species would not be able to cover all of them and certainly all species utilized by prehistoric peoples are not entirely known at the present time. In addition, species such as the gray wolf, grizzly bear, and bison no longer inhabit the region, largely due to human pressure and overhunting. While not all inconclusive, some of the other more common species include pronghorn, mule deer, elk, bighorn sheep, black bear, mountain lion, coyote, badger, swift and gray fox, turkey, cottontail rabbit, jackrabbit, prairie dog, prairie rattlesnake, red coachwhip, golden and bald eagle, great-horned owl, barn owl, red-tailed hawk, and roadrunner

(among others). Bramblett and Fausch (1991) described fish resources available within the

Purgatoire River along with PCMS side canyons. These included channel catfish, central stone- roller, red and sand shiner, flathead chub, fathead minnow, black bullhead, and long-nose dace.

Calhoun (2011) demonstrated that prehistoric peoples also exploited freshwater mollusk species within the region.

CULTURAL OVERVIEW

The following overview, first focuses on caching behavior as it is represented in the archaeological record and through ethnographic studies. In addition, a brief review of the cultural history of the region will be provided, which consists of modified excerpts from Swan and

27 Schriever (2017) or Swan (2009) and relies primarily on data presented by Zier and Kalasz

(1999). Additions to this history will focus on cache assemblages identified within the State of

Colorado that have an associated absolute or relative date, along with the types of materials in association.

CACHING BEHAVIOR

Initial discussions on caching behavior are pertinent to this research, as well as how it relates to each of the temporal periods through the study area. Cache assemblages can have a utilitarian or a ceremonial/afterlife function (Huckell and Kilby 2014; Hurst 2017; Kilby 2008).

In regards to the former, utilitarian caches are comprised of a highly concentrated variety of materials hidden away for potential and/or expected future recovery and utilization. While these caches may include foodstuffs or other organics, the issue of preservation in regards to both recognition of the feature as a cache or as inclusions within an identified stone tool cache assemblage has been recognized (Kilby 2008:30; Kilby and Huckell 2014:1-2; Tunnel 1978:1).

In some Clovis caches, osseous technology in the form of bone rods were identified (Huckell and

Kilby 2014:8) and in Mantle’s Cave along the Yampa River in northwestern Colorado, two caches with well preserved organic material were recovered. One included a coiled net bag that contained the artifacts with grass filling to protect the gear. The other exhibited a flicker feather headdress and feather bundles incased within a deer buckskin pouch (LaBelle 2015:14-15; Burgh and Scoggin 1948). However, these caches are the exception with organics of this state of preservation rarely encountered.

Depending on cache function, the types of materials cached can depend on numerous factors. These include types of raw materials available at certain locations, the quality of those materials for performing anticipated, planned, or unperceived tasks, and the distance of the required resource from the task location or from a more permanent residential base or temporary campsite (Binford 1980; Hurst 2006). Four functional classes are typically associated with cache

28 assemblages (Binford 1979; Hurst 2017; Kilby 2008), which include insurance, passive, load- exchange, or afterlife/ceremonial. Through ethnographic work among the Nunamiut Eskimos,

Binford (1979:256-257) defined the differences between both passive and insurance caches.

Passive gear includes materials designed for a specific purpose and seasonal use. When there is temporal incongruity for the use of this equipment, materials are cached at specific locations where these materials will be needed in the near future. Due to the known tasks associated with these assemblages, the corresponding materials should show relative utility and be of more formalized and finished tool forms, with a large diversity of tool types represented. In addition, consistent maintenance and reuse of these items is likely reflected by a high degree of raw material diversity (Kilby 2008:33-34).

In contrast, insurance gear is typically dispersed through various portions of the landscape in anticipation of predicted or unknown needs during task-oriented activities (Binford

1979). Often these locations exhibit a dependable subsistence base during the time of occupation, but contain either poor-quality or a complete lack of tool stone that can be reliably quarried

(Hurst 2006:104). Cached materials usually are composed of a combination of finished tools as well as materials within earlier stages of manufacture, such as biface and flake blanks or cores

(Hurst 2017:11). For the purposes of an insurance cache, these types of artifacts not only provide immediately usable forms, but also the flexibility to produce additional tools dependent on task needs. With the assumption that the cache location was provisioned with prepared tool stone from a recently visited quarry, Kilby (2008:33) indicates that raw material diversity can be expected to be low. In addition, these artifacts tend to be represented by more generalized forms with a relatively low degree of diversity, which allows for flexibility in the production of stone tool types to fit a variety of task needs. Due to the potential remote nature of these assemblages from a primary residence, these caches are often marked in order to facilitate relocation or are located on easily recognizable landforms.

29 Load-exchange caches are typically located in remote locations in comparison to the base camp or residential site. In these instances, the items procured at the location are of a significant weight or size, and the task group cannot possibly transport all materials (LaBelle 2015:5-9).

Therefore, some of these materials are left behind and presumably consist of the least valuable items. Kilby (2008:33-34) indicates that these tools were likely used and maintained for a specific purpose and as they were only recently removed from economic use, would be expected to exhibit high diversity in raw materials, but also be of relatively low tool type diversity.

Afterlife or ceremonial/ritual caches are unique and are not necessarily intended for retrieval. In the case of the flicker feather headdress and feather bundles identified at Mantle’s

Cave (LaBelle 2015:14-15; Burgh and Scoggin 1948), these items may have been intended for retrieval, as it may be a site location that was regularly returned to, for the conduction of ceremonial activities. However, in most cases, these types of artifacts are associated with burials where the items were not intended for retrieval. Rather, these items appear to be placed with the dead for continued use in the afterlife. Artifacts from these contexts are often covered with red ochre as part of the votive offering (Kilby 2008; LaBelle 2015). These items may have been utilized and maintained by the individual in life, with other newly manufactured materials placed at the time of burial. As such, cache assemblages in these contexts are expected to be of high raw material and tool type variability (Kilby 2008:34).

In addition, prehistoric peoples that left behind these caches may have viewed the landscape in very different ways, depending on whether this was part of an established territory or safeguards placed by explorers or initial colonizers of a new land (Hurst 2017; Kilby 2008:28).

In the case of the latter, these assemblages may contain exotic materials, but be close to nearby quarry locations of similar quality. However, prehistoric peoples would not have been aware of these resources during initial occupation. In contrast, caches left behind by peoples within a known territorial boundary would likely be more strategically placed with a good knowledge of the available resources in different areas of the inhabited region. From this perspective, there are

30 territorial cores, pathways between different core areas (depending on seasonal movement), and perimeters (Hurst 2017:11; Zedeño and Anderson 2015). While core areas are regularly visited and the landscape is well known, the territorial periphery is only sporadically visited with more limited knowledge of these outlying localities. Therefore, caches placed within core areas are more likely to be regularly utilized and replaced with new materials, while caches placed along peripheral zones may be placed with the intention of returning, but due to circumstances may or may not be utilized in the future. These cache types have also been termed continuance and discontinuance caches, respectively (Hurst 2017:11). This type of assessment would require culturally diagnostic artifacts in association with the cache, as well as a larger landscape study identifying the regional extent of possible territory boundaries.

CULTURAL HISTORY OF THE ARKANSAS RIVER BASIN

Three different stages and 10 periods are included within the prehistoric cultural taxonomy for the Arkansas River Basin (Table 2.1), with the Diversification period of the Late

Prehistoric stage being subdivided further into two separate phases – the Apishapa and Sopris

(Zier and Kalasz 1999). The following summary will use this taxonomy as the basis for this discussion.

PALEOINDIAN STAGE (>11,500 TO 7,800 BP)

This is the earliest recognized period of human occupation in North America (Frison

1991:20). This stage, as outlined by Zier and Kalasz (1999), is composed of four separate periods, which include the Pre-Clovis (>11,500 BP), Clovis (11,500–10,950 BP), Folsom

(10,950–10,250 BP), and Plano (10,250–7,800 BP). In comparison to the geologic time scale, this stage encompasses the terminal end of the Pleistocene and early Holocene. Typically, the nomadic hunter-gatherers of this time have been associated with Pleistocene megafauna, including extinct species of bison and mammoth. However, the subsistence base of Paleoindian peoples has been shown to be much more extensive, with utilized remains of horse, camel,

31 peccary, sloth, caribou, elk, rabbit, and fish (to name a few) found within these contexts (Bryan

1991:23; Cassells 1997:71; Greiser 1985:66; Hester 1972; Stanford 1991:5–6; Willig 1991:105;

Zier and Kalasz 1999). The majority of the megafaunal species appear to have become extinct by the Clovis/Folsom transition (LaBelle 2012) with only bison composing the largest of game species in subsequent periods.

Table 2.1. Cultural taxonomy of the Arkansas River Basin (Zier and Kalasz 1999).

Pre-Clovis Period (>11,500 BP)

As mounting substantial evidence of human occupation in the New World prior to Clovis has been found, Waters and Stafford (2014:555) have proposed that this time in prehistory be called the “Exploration Period” rather than Pre-Clovis. This is because the relation of these finds to the later Clovis techno-complex is still uncertain. Clear evidence of these earlier cultures come from sites such as Monte Verde II, Schaefer, Hebior, Paisley 5 Mile Point Caves, Manis, Debra L.

Friedkin, and Lindsay (Waters and Stafford 2014:545–552). Additional sites with compelling early dates include Meadowcroft, Page-Ladson, Cactus Hill, and Topper (Adovasio and Pedler

32 2004; Dunbar 2006b; Adovasio and Page 2002; Goodyear 2002). Based on the cultural components at these sites, this period did not only include biface technology, but also comprised blade/bladelet and osseous technologies. Waters and Stafford (2014:555) also suggest that the

Aubrey site could be a vital resource, as it demonstrates one of the earliest Clovis occupations and contains evidence of bladelet technology, which may indicate a transitional period. While no evidence of Pre-Clovis or Exploration Period sites has been found in southeastern Colorado, the broad technological diversity and the possibility that these sites may not contain traditional

Paleoindian time-diagnostics (Waters and Stafford 2014) is a trend to consider through future investigations.

According to Erlandson (2014:128), the collapse of the Clovis-First model has led to multiple models for the initial entry of the earliest Americans. These not only include the original

Bering Land Bridge and Ice-Free Corridor route, but also a Pacific coastal route or “Kelp

Highway Hypothesis,” a potential Atlantic crossing (Stanford and Bradley 2012), an Arctic “Top of the World” route (O’Rourke and Raff 2010), and a South Pacific migration (Faught 2008) have been proposed.

Clovis Period (11,500 to 10,950 BP)

Lithic technological attributes, including the presence of Clovis fluted lanceolate projectile points, and an association with Pleistocene megafaunal species chiefly defines the

Clovis period, of which cultural groups are typically viewed as highly mobile hunter-gatherers with a largely hunting based subsistence strategy. As documented by many researchers, Clovis lithic technology includes blade and blade cores (conical and wedge-shaped), as well as bifaces of a specific morphology/size with the presence of overshot flaking techniques (e.g. Collins 1999;

Huckell and Kilby 2014; Muñiz 2014; Kilby 2008; Williams 2016). Except for caches, Clovis sites in Colorado include Dent, Dutton, Lamb Spring, Hahn, and Zapata Mammoth (Jodry 1999;

McDonald 1992). While potential Clovis resources have been reported for the PCMS (Owens

33 2015b) and diagnostic isolates have been recovered in the region (Campbell 1969; Bair 1975), the former are non-diagnostic surface remains and further investigation would be needed to confirm these assertions.

Caches attributed to the Clovis period in Colorado include the Drake, Mahaffy, Watts and

CW assemblages (Bamforth 2015; LaBelle 2015; Muñiz 2014; Patten 2015; Stanford and Jodry

1988), which are all located in northeastern Colorado. The Drake cache contains 13 fluted Clovis projectile points with the majority manufactured from Alibates agatized dolomite. Further excavation revealed additional materials comprised of several ivory fragments as well as a large chert hammerstone, of which both ends were heavily pitted from use. Some have suggested this cache functioned as a ceremonial or afterlife assemblage, given the finished nature of the points, their similarity to the Anzick cache, and the presence of ivory. However, there was no evidence of ochre or the identification of burial remnants (Frison 1991; Stanford and Jodry 1988).

The other caches did not exhibit finished Clovis point forms, with several factors considered in regard to temporal or cultural affiliation. The Mahaffy cache includes 11 large bifaces, seven blades, six backed pieces, 31 bifacial-thinning flakes, and 13 core-struck flakes (as well as other indeterminate flake types and natural stone). Several of the flakes exhibit retouch and utilization wear. Material types consist of Kremmling chert from Middle Park, Tiger chert from northeastern Utah, and assorted quartzites (Uinta and Windy Ridge-like). Several of the

Kremmling chert thinning flakes either refit to a larger bifacial core or have strongly related attributes that indicate long flake blanks were being removed for use as knives. As mentioned previously, protein residue analysis revealed artifacts were being used to process camel, horse, sheep, and bear. With the presence of a clear weathering rind on these materials, the camel and horse residues are not likely to be from more recent Old-World introduction, but rather from Late

Pleistocene species (Bamforth 2014, 2015).

Both the CW and the Watts caches exhibit biface reduction techniques and calcium carbonate encrustation indicating an older age with strong arguments for a Clovis affiliation

34 (Muñiz 2014; Patten 2015). The CW cache includes nine bifaces, two biface fragments, and three large flakes and Watts exhibits seven bifaces. At the former assemblage, bifaces exhibit overshot and diagonal flaking attributes (Muñiz 2014). At Watts, there are biface preforms that are of a very large size, which contain tapered bases and beveled facets that appear to be in preparation for fluting. In addition, “platter-like” bifaces are often split in two for ease of creating multiple preforms for point manufacture, which is demonstrated at this site and other Clovis assemblages

(Patten 2015).

Folsom Period (10,950 to 10,250 BP)

This period is characterized by a differing lithic technology compared to Clovis with the smaller fluted point styles of Folsom often found in association with extinct species of Bison antiquus. Other unfluted spear points, called Midland, have also been found in Folsom contexts.

As many of these latter points are usually found in locations a fair distance away from high- quality tool stone resources, it has been interpreted that these points were not fluted to avoid potentially damaging functional tools in remote areas (Hofman 1990). Additional tool types include ultra-thin bifaces, knives, gravers, spokeshaves, scrapers, cores, drills, burin-like implements, choppers, abrading stones, awls, beads, and needles (Zier and Kalasz 1999:86–87).

Pertinent Folsom sites in Colorado include Lindenmeier, Fowler-Parrish, Powars, and Johnson in the northeast (Zier and Kalasz (1999:85) along with Stewart’s Cattle Guard, Zapata, and the

Linger sites in the San Luis Valley (Dawson and Stanford 1975; Jodry and Stanford 1992).

More recent investigations at the Mountaineer and Barger Gulch sites (Stiger 2006;

Surovell and Waguespack 2007) located in higher mountain settings (Middle Park and Gunnison) exhibited evidence of more permanent settlement. At the Mountaineer site, the Folsom occupation is associated with a 4-5 m diameter basin house with a central hearth, along with numerous Folsom projectile points and a wide diversity of tools and flaking debris (Stiger 2006).

These more permanent settlements have led some to suggest that while the plains Folsom period

35 is marked by more mobile groups with a large game focus, the higher mountain Folsom peoples utilized a broader subsistence base with small mammals and plant foodstuffs more commonly utilized (Kornfeld and Frison 2000:148).

Evidence of Folsom occupation on the PCMS is limited with the majority of the artifacts consisting of Folsom or Midland points that were either discovered as isolated finds or within deflated and mixed surface remains where multiple occupations from a broad period of prehistory are observed, likely indicating curated specimens. Owens et al. (2012) described site 5LA7419 to potentially contain a Folsom assemblage with a Midland projectile point, a channel flake (from fluting), a potential ultra-thin biface, and many associated artifacts with carbonate coatings.

While these materials are also located within a mixed surface context with more recent Archaic and Late Prehistoric diagnostics, the overall unique nature of this concentrated assemblage within the site boundaries indicates the possibility of Folsom use (Owens 2015b). No known caches attributable to the Folsom period have been discovered in Colorado.

Plano or Late Paleoindian Period (10,250 to 7,800 BP)

While there is no shortage of evidence for large game utilization in the previous periods, there is an apparent change in hunting strategy during the Plano period, as the numbers of communal kill sites seem to rise dramatically (Stanford 1974; Wheat 1972; Wilson 1974;

Wormington 1984). Technologically, this period exhibits a proliferation of projectile point types.

Many of these points have been found in association with each other in various contexts and several complexes have been defined based on these differing styles: Hell Gap/Agate Basin,

Alberta, Cody, Frederick, and Lusk (Zier and Kalasz 1999:91–92). Significant Plano sites in southeastern Colorado include Olsen-Chubbuck (Wheat 1972), Runberg (Black 1986), and

5LK372 (Arthur 1981). While sites like Olsen-Chubbuck exhibit lithic materials from a wide variety of exotic sources and indicate highly mobile populations like the previous Clovis and

Folsom periods, several Plano resources are starting to show evidence of local lithic reduction

36 strategies. It has been suggested that this trend may reflect increasing regionalism by certain groups of the period (Pitblado 2003; Stanford 1999).

While there are a few Plano period sites on the PCMS with evidence of multiple projectile point diagnostics, these locales have been shown to contain little depositional integrity.

Additional isolates or potentially curated points have been classified as Hell Gap/Agate Basin,

James Allen, and Cody Complex styles. It is interesting to note, that most of these projectile points are manufactured from known local tool stone sources and this trend toward regionalism is also manifested by the limited Plano period diagnostics represented at the PCMS (Owens 2015:3-

7 - 3-9). While large bison kills are commonly associated with this period, the evidence for regionalism certainly indicates lower mobility groups that rely on a broader subsistence base.

Identified in northeastern Colorado, the only cache assemblage associated with the Late

Paleoindian period is the Buffman Creek assemblage (LaBelle 2015:16; Burns 1996). The artifacts were stored within a small crevice and included a James Allen lanceolate. Materials identified included 14 bifaces, a projectile point, eight scrapers, 11 flake tools, and two flakes.

Raw material types were from a broad range of local sources, which may indicate a passive or seasonal function.

ARCHAIC STAGE (7,800 TO 1,850 BP)

This broad span of cultural history is temporally separated primarily by changes in projectile point morphology and includes the Early Archaic (7,800–5,000 BP), Middle Archaic

(5,000–3,000 BP), and the Late Archaic (3,000–1,850 BP) periods (Zier and Kalasz 1999). With the exception of the Early Archaic, this stage is well represented in the archaeological record throughout the PCMS and adjacent regions.

Early Archaic Period (7,800 to 5,000 BP)

While site components of this period are still infrequently identified on the plains, some

Early Archaic sites have been recently documented at the edge of the plains and along the lower

37 eastern foothills of the Colorado Rockies (Anderson et al. 2013; Sherman and Ziedler 2011), with additional campsites also reported for northeastern Colorado (Anderson et al. 2010). With the exception of these resources, southeastern Colorado sites have mainly consisted of sparse surface projectile points with no prior datable materials being recovered (Zier and Kalasz 1999:102).

This overall lack of evidence for Early Archaic settlement throughout the plains has led some to hypothesize (Benedict and Olsen 1978; Buchner 1979; Reeves 1973) that the area could not sustain long habitation periods with most groups moving into the higher mountains due to the effects of the Altithermal climatic episode. However, further research should be conducted before abandonment of this level is fully considered. While the Altithermal may have had an impact on Early Archaic lifeways, to what extent, is still up for debate. Especially considering that the region had been inhabited for so many years prior to this period. In addition, geomorphological processes may have created issues in regards to site discovery (deeply buried) or preservation (erosion) of these resources (Zier and Kalasz 1999).

Technologically, the Early Archaic is commonly associated with large projectile points exhibiting low, shallow side notching. These types of points have been found in the Indian Peaks of the Colorado Rockies (Benedict and Olsen 1978) and throughout the plains. Other projectile point types include the Albion Boardinghouse points identified by Benedict (1975), unstemmed projectile points, to include the tear-drop shaped styles found at Magic Mountain (Irwin-Williams and Irwin 1966:66–70), and broad corner-notched points with convex blade edges and basal notching (Frison 1991:79–86). However, many of the latter types have been found throughout a broad period of the Archaic stage and are not definitively Early Archaic in age (Zier and Kalasz

1999:105–106). Due to minimal site representation on the plains, the full expanse of the Early

Archaic toolkit is still uncertain.

In 2010, Centennial Archaeology, Inc. identified two sites located along the lower foothills and to the west/northwest of the PCMS, which were dated to the Early Archaic period.

These included a campsite with a hearth and associated debitage and stone tools; and a habitation

38 locale where two basin houses and a thermal feature were identified (Anderson et al. 2013). The sparse nature of the associated artifact assemblage may suggest a short-habitation period as indicated for the mountain refuge hypothesis, but this is still based on an overall small sample size.

Another recently investigated site, 5EP5906, is located on the Fort Carson Military

Reservation (Sherman and Ziedler 2011:3-263 to 3-277). This rockshelter is located on a low- lying ridge that borders a minor tributary to the Arkansas River, along the foothills of the Rocky

Mountains. Two hearth features located 40–68 cm below the excavation unit datum were identified, of which one was dated to 6,650–6,480 cal BP. No faunal remains were recovered from the fill, but charred remains of grape (Vitis), goosefoot, amaranth, purslane, and rice grass seeds indicate plant food resources utilized. Non-diagnostic chipped-stone tools were found in the upper excavation levels and are not clearly associated with the hearths, with only debitage found within the features and the surrounding matrix (Sherman and Ziedler 2011:3-263 to 3-277).

Potential Early Archaic components have been documented on the PCMS. However, there is very few that exhibit potential for intact deposits (Owens 2015b:3-9 - 3-10). The best evidence for Early Archaic occupation identified thus far is a shallow basin hearth that was discovered during excavations at the Barnes site (Ahler 2002:97-98). There were no artifacts identified in association with only fire-cracked rock and scattered charcoal recovered.

In the State of Colorado, two caches have been identified that either date to the Early

Archaic or to a transitional period with the Middle Archaic (Metcalf and McDonald 2015). These caches are located along the Yampa River Valley in the northwest portion of the state. At site

5MF2990, Metcalf and McDonald (2015:113-114) identified a stone tool cache buried along the floor of a basin house with an associated radiocarbon date of 5,970 BP. Items within this assemblage included 11 large bifaces and performs and four retouched/utilized flakes, all manufactured from a high-quality exotic chert. The other cache consists of eight manos and dates to the Middle Archaic transition based on association with a dated paleosol and hearth (Metcalf

39 and McDonald 2015:114-115). Given the location, within more permanent habitations, these appear to have functioned as seasonal or passive gear assemblages.

Middle Archaic Period (5,000 to 3,000 BP)

At the beginning of the Middle Archaic, the PCMS and the greater Arkansas River Basin region sees a dramatic rise in site quantity, suggesting settlement was not only becoming widespread, but a regional increase in population was occurring. While the lack of Early Archaic sites seems to be partially due to geomorphic processes, these differences are so drastic, that a rise in population is seen as more likely and may represent migration of Early Archaic peoples to the area (Zier and Kalasz 1999:116–117).

Many sites of the Middle Archaic exhibit evidence of McKean Complex lithic technology, which include McKean lanceolate, Mallory, and Hanna-Duncan projectile point styles. While all of these point types have been found at sites like Signal Butte (Forbis 1985), they are also found separately at other sites (Frison 1991). This has led some researchers in the past to suggest that these different forms are a reflection of “stylistic markers” of different groups who engaged in various seasonal interactions (Wheeler 1954). Others have proposed functional differences as either spear points or atlatl darts (Davis and Keyser 1999; Larmore 2002:5). In his research, Larmore (2002) indicates that McKean Complex peoples likely moved onto the plains of Colorado from the north, given the fact that all known Colorado sites date later than Northern

Plains manifestations. Additional point styles have also been described that have not shown a direct relationship to the McKean Complex. These forms typically consist of large, broad corner- notched specimens with slightly variable stem and base shapes, some of which have been associated with higher mountain setting (Mountain Tradition) or American Southwest cultural groups (Anderson 1989; Gunnerson 1987).

Subsistence practices during the Middle Archaic are suggested to have broadened, as a general increase in ground stone and the more common appearance of food preparation pits are

40 noted (Frison 1991:89). Features of this type range widely in dimension and can be completely slab or cobble-lined, of a slab-lined earthen basin design, or comprised of less formal pit hearths

(Frison 1991:92–97; Anderson 2008; Kalasz et al. 1993). However, due to the overall lack of subsistence or feature data on the plains during the Early Archaic, it is difficult to interpret these temporal changes. While the Wyoming Basin and Northern Plains exhibits a proliferation of basin houses (Zier and Kalasz 1999:120) and spaced-stone architectural units have been documented during the Middle Archaic (Frison 1991:92-97), there have been very few structures identified in southeastern Colorado during this time. The main evidence for Middle Archaic habitation has been found in rockshelters and preservation issues may be a reason for the lack of open-air architectural site discoveries. Rood (1990) documented a basin house that exhibits a partial rock alignment (semi-circular), which dates to the transitional period between the Middle and Late Archaic. One of the basin houses identified along the upper Apishapa River by

Centennial Archaeology, Inc. dated to the Early Archaic and Middle Archaic transition (Anderson et al. 2013) and additional basin houses have been documented in Douglas County to the north

(Gantt 2007). While based on a small sample size, this seems to indicate the use of these structure types within open-air settings.

The earliest accepted rock art on the PCMS is dated to the Middle Archaic. These motifs tend to consist of abstract designs in the form of pecked curvilinear or rectilinear elements

(Loendorf 2008). There are no cache features directly dated to the Middle Archaic period, apart from the mano cache described previously that appears to date to the transitional period with the

Early Archaic. However, at the Hells Midden site, along the Yampa River in northeastern

Colorado (5MF16), there is a cache of five manos that are in the same level as a recovered

Mallory point type (LaBelle 2015:15), which may indicate a Middle Archaic and potentially a

McKean Complex association.

41 Late Archaic Period (3,000 to 1,850 BP)

Increased site density and numerous absolute dates for the Late Archaic period seems to indicate more intensive occupation of the region and a general increase in population (Zier and

Kalasz 1999:126–140). At many resource locales, there are continuous occupation layers that span the Middle to Late Archaic periods, which has led some investigators to conclude that these expanding populations stemmed from local Middle Archaic groups inhabiting the region (Kalasz et al. 1993; Zier 1989).

Late Archaic projectile points exhibit wider morphological variation than in any previous time. Some forms persist from the Middle Archaic; however, the indented base characteristics of the McKean Complex are nearly absent from these contexts. Although there is more diversity in projectiles, several key attributes are observed in these variants. All are dart or spear points that usually exhibit broad blades, deep corner-notching, with expanding stems and straight or concave bases; narrow blades with shallow corner-notching, expanding stems and straight to concave bases; or unshouldered points with variable blade widths, straight or contracting stems with convex bases (Anderson 1989:232–233; Hand and Jepson 1996:66; Jepson et al. 1992:134–166;

McKibbin et al. 1997:62–67; Simpson 1976:49; Van Ness et al. 1990:115–197; Zier 1989:138;

Zier and Kalasz 1999). Lithic industries, both chipped stone and ground stone, are virtually indistinguishable from the Middle Archaic period, which has been viewed as further evidence to support a continuum of local technology and expansion of the previous Middle Archaic populations (Zier and Kalasz 1991). This broad trend of large corner-notched point forms is noted throughout the plains (Frison 1991:101–109).

Settlement patterns and subsistence practices of the Late Archaic also appear as a continuum of the Middle Archaic, with the exception of the potential introduction of maize horticulture (Zier and Kalasz 1999:137). Southeastern Colorado sites suggest occupation of a wide range of environmental settings to include several open-air and sheltered locales. In terms

42 of subsistence, the Late Archaic inhabitants seem to a have a broader base; however, this could be a result of not only preservation issues, but also the larger database of Late Archaic components.

Rock art motifs of this period still tend to consist of abstract elements, but also include more common representations of quadrupeds (Loendorf 2008).

Two caches in Colorado have been dated to the Late Archaic period, one of which lies within the Arkansas River Basin. This assemblage was identified to the east of Pikes Peak within

El Paso County (Cunnar and Chambellan 2014). The artifacts were found in direct association with a hearth feature that produced a radiocarbon date of 2,840 ± 30 BP. Materials identified include three bifaces, eight formal or patterned scrapers, and 16 utilized flakes. Single specimens of a flake drill, graver, multi-directional core, scraper preform, secondary core reduction flake, tertiary flake, and a utilized blade-like flake were also identified. Material types were of a low diversity and included Black Forest silicified wood (33) from the Palmer Divide (a short distance to the northwest) and a single specimen of Alibates chert from the panhandle of Texas. Five of the flakes are blade-like with evidence of biface reduction and overshot removal. The blade-like flakes were compared to other blades from Clovis and Late Prehistoric assemblages in Texas.

This comparison showed that the curvature and length/width ratios of the 5EP4826 blades more closely resembled those from Late Prehistoric contexts (Cunnar and Chambellan 2014). Given the close association of the hearth and the range of artifacts, this cache appears to have functioned as a seasonal or passive cache, although the low diversity of raw materials seems to go against the expectations for this cache function as described by Kilby (2008:33).

The other cache dating to this period was found along the northern boundary of the

Palmer Divide in northeastern Colorado (Gilmore 2015). This cache was comprised of only

Black Forest silicified wood (also known as Dawson petrified wood) raw materials and appeared to have been reduced from a single core, as several of the specimens were refit to the parent piece. Artifacts included a bifacial core and 26 pieces of debitage. As Black Forest silicified wood can be found and quarried along the Palmer Divide, this cache may be located fairly close

43 to the actual procurement area. However, high to medium-quality tool stone from this outcropping can be widely dispersed and difficult to find, making the need of caching relevant to prehistoric peoples inhabiting the region. Gilmore (2015:108) also states that the tool stone of the cache is not of the highest quality and may not have been worth the cost of transportation. Based on this interpretation, this assemblage likely represents a load-exchange function.

LATE PREHISTORIC STAGE (1,850 TO 225 BP)

This stage is represented by three periods of time, the Developmental (1,850–900 BP), the Diversification (900–500 BP), and the Protohistoric (500–225 BP). The Diversification is further divided to include the Apishapa phase (900–500 BP) and the Sopris phase (900–750 BP).

The beginning of this stage is typically associated with the introduction of bow-and-arrow technology, ceramics, increased utilization of domesticates including maize horticulture, and the more common occurrence of stone architecture. However, the date of introduction for each of these innovations varies from region to region and has generally caused different investigators to provide a wide range of dates for the beginning of this stage, which have fluctuated from Anno

Domini (AD) 1 to AD 450 or 1950 to 1500 BP (Alexander et al. 1982; Campbell 1969; Eighmy

1984; Hunt 1975; Lintz and Anderson 1989; Zier 1989; Zier and Kalasz 1999:142).

Two caches within the state can be placed within the Late Prehistoric, but could not be directly dated and contain technology or diagnostics of a broad temporal range related to the stage. The Easterday II cache is located in northeastern Colorado and is comprised of 99 flake cores, two bifaces, and a unifacial scraper with all raw materials composed of Flattop chalcedony.

This tool stone resource outcrops 97 km to the northeast of the cache (Basham and Holen 2006).

While no diagnostics were observed and overshot flaking techniques are represented in the assemblage, the morphology of the flake scars removed from the cores are comparable to flake blank sizes required for bow-and-arrow projectile point manufacture. In addition, identified sites within the area contain projectile points of Late Prehistoric styles, all are exclusively

44 manufactured from Flattop chalcedony, and the points exhibit size ranges comparable to the flake scars of the cores at Easterday II. Given the location of the assemblage, either a load-exchange or insurance cache function is inferred (Basham and Holen 2006).

The other cache was identified northeast of Denver. Named the Westfall/Wagner cache, this assemblage included 10 small, triangular projectile point preforms, three large bifaces, and 15 flakes of various sizes. With the exception of three artifacts, all were manufactured from a red

Hartville Uplift dendritic chert from southeastern Wyoming. While the cache was not found in context, the preforms are of a size and morphology that is very common in Late Prehistoric assemblages (Westfall 2015). Based on the isolated nature of the assemblage and artifact attributes, an insurance function seems likely.

Developmental Period (1,850 to 900 BP)

Starting early on in the Developmental period, the archaeological record typically contains small, corner-notched projectile points (e.g. Scallorn) or small un-notched points (e.g.

Fresno) suitable for use with a bow-and-arrow. While ceramic technology is observed at several sites, the assemblages are usually sparse or in some cases, not represented at all. After excavations at Recon John on Fort Carson, Zier (1989) suggested that ceramics were not initially relied on by Developmental peoples and a date of 1,350 BP was proposed for the regular use of ceramics in the southeastern Colorado region. The remainder of the lithic tool industry is remarkably similar to that of the preceding Late Archaic and many large dart forms persist into

Developmental period components (refer to Dwelis et al. [1996: Figure 6D], Hoyt [1979: Figure

6], and Loendorf et al. [1996: Figure 4.35a]; Zier and Kalasz 1999), which likely signify a continuation of atlatl use.

While the prolonged use of basin houses is apparent in some areas (Zier and Kalasz

1999:172; Hunt 1975), stone enclosure architecture and semisubterranean pithouses are noted through the larger Arkansas River Basin and at the Park Plateau, respectively. Studies at the

45 Forgotten Site on the PCMS (Loendorf et al. 1996) documented larger concentrations of grass pollen within the stone enclosure interior, indicating that the circular, upright sandstone walls contained an overlying thatch roof. Increasing numbers of sites and radiocarbon dates for the area may indicate population growth; however, this could be the result of higher visibility site locales, particularly in open settings (Zier and Kalasz 1999:171). Subsistence practices still maintain a broad base with a wide assortment of wild foodstuffs utilized. While maize is present in many site contexts, the evidence at each locale is scant and too what level maize horticulture was practiced is uncertain (Zier and Kalasz 1999:176-178).

Piñon Canyon rock art during the Developmental period tends to show a reduction in abstract elements with large numbers of quadrupeds often depicted as well as anthropomorph

(human) figures. Some rectilinear grid motifs are noted in association with panels that portray large numbers of quadrupeds, which appear to represent nets and potentially depict game drive scenarios (Loendorf 2008). There are no known cache assemblages that can be confidently placed within this period.

Diversification Period (900 to 500 BP)

The beginning of the Diversification period is identified by the construction of larger multi-room enclosure structures and a more sedentary lifestyle (in general) for the inhabitants of the Arkansas River Basin. Two phases within the Diversification, the Apishapa and the Sopris appear to be related, but also seem to have differing cultural ties and influences. Apishapa populations show a strong influence from the eastern Plains Village people and the Sopris seem to have maintained ties to the Puebloan Southwest. This is not only seen through differences in material culture, but through a contrast in architectural styles. While there is a great deal of variability in both, Sopris architecture generally displays rectangular walls with adobe or jacal construction, while Apishapa structures exhibit curved rock walls with vertically placed slabs more often incorporated. Sopris architecture also contains formalized interior features, such as

46 mud-collared hearths (Zier and Kalasz 1999:196). Many investigators believe these two phases represent a common origin with a subsequent split due to these external influences (Kalasz 1988;

Lintz 1984; Mitchell 1997; Wood and Bair 1980; Zier and Kalasz 1999:189; Zier et al. 1988).

However, some researchers have proposed that the Sopris represent an Athabaskan migration into the region largely based on dental attribute comparisons (Schlesier 1994; Turner 1980).

The presence of Developmental period components underlying several large Apishapa architectural sites (Cramer, Mary’s Fort, Ocean Vista, and Avery Ranch) has indicated that the transition between the two periods was gradual and potentially tied to changes in local population lifeways (Gunnerson 1989; Kalasz et al. 1993; Zier and Kalasz 1985; Zier et al. 1988). However, some site investigations also documented disturbed contexts between Developmental and

Diversification materials, making differentiation between the two difficult to separate. Due to this, Zier and Kalasz (1999:191) have suggested that some of these sites may have been reused and occupied for many years, potentially spanning both of these periods of the Late Prehistoric stage.

While these architectural sites are highly visible on the landscape and the majority of the research has focused on Apishapa and Sopris manifestations, it is likely that other groups inhabited the region, perhaps as more mobile hunter-gatherers that interacted with Apishapa or

Sopris peoples. At the PCMS, potential interactions with other groups inhabiting the region are represented in two ways. Firstly, many architectural sites of classic Apishapa stone enclosure construction are located along promontories or high cliff face “islands” within the canyons that appear to represent defensive positions (Owens 2007). Therefore, these interactions may have been under more violent and combative circumstances. Secondly, there is mounting evidence of an additional cultural manifestation in southeastern Colorado. Termed the “Barnes culture” by

Owens (2015b), sites attributed to Barnes are typically located along the open grassland or woodland margins, exhibit unique ceramic ware types (Lindsey and Krause 2007:101-102), and

47 show a wide variety of exotic tool stone, certainly indicating a more mobile lifestyle (Ahler

2002).

With the exception of changes in some projectile point forms and the apparent increase in ceramic use, technology during the Diversification did not differ from the preceding period.

Small, side-notched projectile points (e.g., Washita/Reed), most notably at Apishapa sites, dominate assemblages in contrast to the corner-notched variants of the Developmental. However,

Sopris sites still exhibit these small, corner-notched point styles, which may have been a more advantageous design based on differences in subsistence strategy (Wood and Bair 1980; Zier and

Kalasz 1999). Puebloan Southwest ceramic wares are found throughout southeastern Colorado, but are more indicative of Sopris phase sites, whereas Apishapa contexts exhibit local cord- marked or polished wares. Although maize horticulture appears to be occurring at this time, the level of reliance on this crop is uncertain, as a variety of wild plant resources are still abundant in the archaeological record (Van Ness 1986). Alternatively, the presence of domesticates in the region may be a result of trade with people from the American Southwest.

Diversification rock art at the PCMS shows similarities with the Developmental period; however, anthropomorphs are much more common and in several panels appear to be either chasing animals (in a game drive situation) or display postures associated with dancing. In addition, gradual differences in quadruped attributes are witnessed between the early

Developmental and into the Diversification to include variations in how hooves or antlers/horns are depicted (Loendorf 2008).

While the cultural taxonomy for northwestern Colorado differs from the Arkansas River

Basin, a single cache identified within the Yampa River Valley was dated to the early portion of this period (954 to 760 cal BP). The cache assemblage was identified during excavations at the

Mantle’s Cave site (5MF1) and included a flicker feather headdress, feather bundles, an elongate biface, and a broken scraper placed within a deer buckskin pouch (LaBelle 2015:14; Burgh and

Scoggin 1948). Due to the unusual and excellent preservation of organics at this locale, this

48 unique assemblage seems to point to a more ceremonial function, perhaps conducted during certain times of the year at the cave.

Protohistoric Period (500 to 225 BP)

Prior to regular Spanish expeditions in the early 1700s (AD), along with French and later

American incursions, both direct and indirect influences by European colonizers were infrequent within the Arkansas River Basin. While sparse historical accounts give some valuable evidence regarding Native American use of the region, the start of this period is poorly dated and future refinement is needed. According to Zier and Kalasz (1999:250), the beginning of the

Protohistoric period should mark the overlapping timeframe when Apishapa sites were abandoned and the migration of Athabaskan-Apachean peoples into the region from the north are documented. Subsequently, the end of the period represents an approximate time interval when the Comanche reportedly pushed the Apache bands to the south and out of southeastern Colorado, which coincides with a general increase in historic records from the beginning of the 18th century forward. Other tribes known to have intermittently occupied the western margin of the Central

Plains in the Protohistoric to early Historic periods include the Ute, Cheyenne, Arapahoe, and

Sioux (Jones et al. 1998).

By the mid-1600s, Rio Grande Puebloans began fleeing their homelands due to Spanish oppression (Carrillo n.d.; Hill Jr. et al. 2018). Some of these refugees may have traveled through the PCMS and potentially inhabited the region on a short-term basis. However, many of these groups were reportedly traveling to a place called “El Cuartelejo” by the Spanish (translated as

“the far quarter”), which is thought to consist of a series of villages through a broad geographic region that appears to include eastern Colorado, western Kansas, and potentially southwestern

Nebraska (Wedel 1986:139). Spanish accounts associate these settlements or “rancherias” with the Apache and at the Scott County Pueblo in western Kansas, there is evidence of Southwestern architecture as well as artifacts and features from both the Rio Grande Puebloans and the Dismal

49 River Aspect (Hill Jr. et al. 2018). While the latter is thought to represent the ancestral Apache,

Gulley (2000) has argued that these site types are representative of a general Plains lifeway and cannot be definitively attributed to the Apache. According to historic documentation these settlements lied to the north of the Arkansas River (Carrillo n.d.) and there does not appear to be any direct evidence of these rancherias in the PCMS region (Zier and Kalasz 1999:251).

The various bands of the Apache were known for their ability to adapt to their environment and modify their settlement/subsistence strategies based on landscape conditions and adaptations perfected by resident populations (Wedel 1986:147-148; Zier and Kalasz 1999:251).

As such, there appears to be a wide variety of architectural styles and subsistence practices that can be attributed to the Apache as they settled into various portions of the Central and Southern

Plains. While some groups maintained a highly nomadic lifestyle with the use of dog or horse travois and hide tipi structures, along with a reliance on large game bison hunting; others were evidently influenced by the Rio Grande Puebloans, the Shoshonean bands of the Rocky

Mountains, and the Caddoan groups of the eastern plains. These more sedentary populations exhibit evidence of more substantial architecture and a broader economic base that included a variety of domesticates and native resources (Zier and Kalasz 1999:250-259). Presently,

Protohistoric structures on the PCMS appear to consist of spaced-stone circles or tipi rings and a single site exhibits evidence of wickiup style architecture (Dodson 2012). While some of the spaced-stone circle sites are indicative of the Apache due to radiocarbon dating and/or ceramic ware types (Zier and Kalasz 1999:257), the remainder may be attributable to the Apache, Ute or later mobile Plains tribes (e.g. Comanche, Cheyenne, Sioux) known to have frequented the region.

Rock art studies at the PCMS show a strong relationship to the Apache, with differing motifs appearing to represent gan dancers or Apache mountain spirits, along with bison representations that exhibit heart lines. At the Smith dike, to the south of the PCMS, there is a

“lightning” gans figure identified in association with a small stone structure that may represent a

50 vision quest site. In addition, the Stone Structure site, located on the Hogback of the PCMS, exhibits differing rock art elements interpreted to be of potential Apache association and an architectural style similar to the Smith dike manifestation (Loendorf 2008:168-184).

Material culture remains of Protohistoric age appear to be rare within southeastern

Colorado. The most widely recognized diagnostic artifact is the micaceous ceramic ware, which have been associated with various Apache groups (Baugh and Eddy 1987; Brunswig 1995;

Gunnerson 1987; Hummer 1989). However, some investigators suggest that these micaceous wares are not a reliable indicator of cultural affiliation (Brunswig 1995; Gulley 2000).

Otherwise, projectile points recovered from Protohistoric contexts and the general lithic and ground stone industries show little differentiation from earlier Diversification period sites. Point forms of Reed, Washita, Fresno, and Haskell styles have been identified at several of these locales (Zier and Kalasz 1999). While Avonlea projectile points have been infrequently documented (e.g. Swan 2009), these point variants have been described for the Platte River Basin to the north. These styles are suggested to be antecedent to Protohistoric Apache groups (Zier and Kalasz 1999:253; Brunswig 1995) and are dated to the Early to Middle Ceramic periods in the Platte River Basin (Gilmore et al. 1999) or the Developmental to Diversification periods of the Arkansas River Basin. In addition, the introduction of metal and glass items, to include metal projectile points, may be represented in these contexts. Prior to this research, no known

Protohistoric caches are documented in the state.

While the cache at Draper Cave (5CR1) has not been dated, it deserves a special mention.

This assemblage is located within the Arkansas River Basin and was identified within deposits that can only be confirmed to be of a younger age than the Middle Archaic. It consists of an afterlife cache, in which 38 bifaces and/or knives were found amongst a prehistoric burial

(LaBelle 2015:13; Hagar 1976).

51 CHAPTER III

METHODOLOGY AND DATA COLLECTION

The purpose of this research is to investigate the geomorphology of the Owens Cache site and potentially provide an absolute or relative date for the assemblage. Based on the lithic technological attributes of the stone tools and the exotic materials they are manufactured from, it has been proposed that the cache is associated with a potential Paleoindian utilization of the landscape (Owens 2015a). Given the prospective of a remnant intact component of the feature being identified, the geomorphological study of the landform deposits and the possible recovery of suitable organics and/or more definitive diagnostic artifacts for dating the assemblage should be acquired, providing several lines of evidence to prove the research question of a temporal or cultural affiliation related to Paleoindian lifeways.

INITIAL SURVEY AND LANDFORM ANALYSIS

Investigations of the cache include a surface reconnaissance to determine if recently exposed artifacts or deposits are witnessed that differs from the 2010 reevaluation of the site.

Due to the limited extent of the feature boundaries (4 x 2 m), as defined from the 2010 site assessment, transects spaced at 1 m apart are conducted with any artifacts or unexpected landform attributes pin flagged for further evaluation.

In order to analyze the cache within a broader landscape context, a scaled slope profile of the canyon is drawn from the upper terrace edge to the main channel thalweg, which follows the guidelines set forth in Rapp (1967) and Savigear (1967). During this recording, a profile line is established and oriented along the steepest sections of the canyon profile, to include the location of the cache feature. A 50 m steel tape is stretched along this line with slope inclination and notes regarding slope attributes recorded at 1 m intervals. A Digi-Pas® DWL-80E inclinometer with a

0.1° resolution is utilized for measuring slope angle. When abrupt changes in elevation are noted and are less than a meter in length, these sections are more carefully mapped and the surface

52 manifestation of this break documented. Additional notes include changing orientations of the slope, the shape of slope breaks, areas of exposed bedrock, rock size and morphology, and evidence of differing clast lithology.

As described in the following chapter, the sandstone outcropping where the cache was identified collapsed at some point in the past. This event not only exposed the cultural materials of the cache, but also resulted in a situation where several large boulders were overlying the deposits believed to contain the subsurface components of the assemblage. In order to provide access for the excavation of these deposits, the locations of the major boulders are mapped in with a Nikon® DTM-322 total station and subsequently removed from the excavation area.

During this process, very minor slumping of the deposits is identified with the sharp, more compacted boundaries of the boulder depressions maintained throughout the majority.

EXCAVATION PROCEDURES

The primary data needed for this study are obtained through controlled excavation of the cache feature. Initial excavation units are placed along the southeastern side of the cache, with the grid northing being offset 30° to the west of true north in order to accommodate for the natural orientation of the landform. A total of four 1 x 1 m excavation units are aligned at a perpendicular angle to the terrace, in order to bisect the cache area. Establishment of these units is measured using the Nikon® DTM-322 total station, and all additional spatial measurements utilize this same instrumentation. Each of these units is carefully excavated in 2 cm levels in order to obtain high spatial resolution mapping and tight control of artifact provenience. When an abrupt stratigraphic break is observed through the course of level excavation, the level is terminated at this contact. Following this methodology ensures that no sediment samples are collected that cross these stratigraphic boundaries. All of the excavated soil matrix within the cache boundaries is collected.

53 In addition, separate collection of samples may occur when concentrated areas of charcoal or other organic materials are found during the course of excavation. These samples may also be used for additional soil analysis needs, such as measuring soil textural differences or varying humic levels within the strata. Once the necessary geomorphological and radiocarbon data are obtained, all remaining samples are either sent to PaleoResearch Institute for specialized analysis or waterscreened with 1/16th inch mesh and processed for material culture.

While additional trench excavation units are placed, no further excavation units can be established within the cache boundaries after the four bisecting units have been completed. This ensures that a portion of the cache matrix will remain intact for future investigations and additional paleoenvironmental data can still be obtained. Given the small 2 cm level increments of the cache excavation and the resulting small sample sizes within each of the units, larger samples collected from the side walls are needed in order to have the sediment volume (50 grams of less than 2 mm size grade) necessary for textural and other soil analysis needs. In addition, careful precautions are taken in the handling of artifacts as they are discovered through the course of excavation. Any excavator is to physically touch no artifacts and these materials are collected without direct contact in order to avoid contamination. By collecting the artifacts in this manner, the possibility of protein residue analysis can be considered.

In order to provide a large enough window to examine the geomorphology of the overall landform and establish a depositional history for the terrace, additional 1 x 1 m excavation units are placed, which extend off of the original four excavation units placed to bisect the cache. It is anticipated that two excavation units are necessary upslope of the cache with three more placed downslope. These excavation units are dug in more conventional 10 cm levels with abrupt changes in strata or previously recognized gradual strata changes also being taken into account for excavation level termination. All fill from each of these excavation units are dry-screened with 1/8th inch mesh and a standard 1/9th (33 x 33 x 10 cm) sediment sample collected for waterscreening (1/16th inch mesh size). When potentially significant cultural materials are

54 encountered through the course of the larger trench excavations, excavation procedures outlined for the cache feature are followed.

Once the trench is established, the stratigraphy of the landform can be mapped in detail and additional sediment samples obtained. Samples are collected in 10 cm intervals from the stratigraphic column; however, no samples will cross stratigraphic boundaries. Samples near contacts are collected from the top and bottom of each layer for comparative purposes in order to assist with the geomorphological investigation of the site through laboratory soil analysis and potentially acquiring organics that can be compared to the cache for indirect dating purposes. In the event that suitable organics within the cache itself is not found, radiocarbon dating of the trench stratigraphy and correlation of the strata is vital to establishing a temporal affiliation for the assemblage. If suitable organics are not identified during excavation work, equipment necessary for the collection of sediments for Optically-Stimulated Luminescence (OSL) dating is available. This includes black plastic in order to minimize exposure to sunlight and open-ended opaque PVC tubes for proper storage. If this contingency proves to be necessary, an expert consultation regarding proper collection procedures is needed.

During excavation, all units, the trench, and vertical elevations are digitally mapped with the use of a total station. New surface artifacts, the site boundary, and the modern topography of the site surface are included within the final digital map of the site locale. In addition to these standard-mapping techniques, a Light Detection and Ranging (LiDAR) scan of the main cache area; to include the open trench is conducted in order to obtain a three-dimensional model of the landform. A Leica-Geosystems® Scan Station C10 instrument is utilized for this portion of the investigation. This work may reveal landform characteristics that are not readily visible to the naked eye and assist with the geomorphological interpretation of the locale.

Post-excavation procedures include backfilling of the open trench with an attempt made to preserve the trench walls and prevent unwanted erosion of the feature after the field investigations are complete. Due to the collection of cache deposits and the loss of sediment as a

55 result, sterile deposits from the bottom of the channel are utilized to properly backfill the trench and ensure a return to pre-excavation conditions. Continued monitoring at the locale should be conducted to ensure vegetation regrowth and stabilization of the landform has occurred.

LABORATORY PROCEDURES

All fill collected from the excavation are either waterscreened with 1/16th mesh or utilized for specialized analysis. Samples collected in direct association with intact subsurface artifacts are sent to PaleoResearch Institute in Golden, Colorado for charcoal identification,

Accelerator Mass Spectrometry (AMS) dating, elemental composition analysis, and recovery of macrobotanical remains. Any radiocarbon dates obtained are reported as uncalibrated in all of the site documentation. Stone tools recovered from the excavation are also considered for protein residue analysis. Additional specialized analyses performed on the samples collected from the sidewall stratigraphy include sediment texture and humic level studies. Any remaining fill from these samples is waterscreened.

Processing of waterscreen samples are keyed towards artifact and faunal remain recovery, the identification of potential datable organics, other anomalous materials, and natural (not culturally modified) rock lithology types. In regards to the latter, each rock lithology represented, of greater than 2 cm in size, are sorted and weighed using an hanging scale for larger proportions and an Ohaus® CS series scale (with 0.1 gram accuracy) for smaller proportions. Additional data recorded for these rock categories include a largest clast size measurement and rock fragment roundness based on the criteria set forth in Schoeneberger et al. (2002). These data not only provides the types of lithologies represented in the matrix, but also the relative proportion of rock increases (or decreases) in the soil matrix with depth, as well as potential transport distances. All cultural artifacts recovered are analyzed, described, and curated according to the standards defined by the Fort Carson Cultural Resources Management Program (CRMP).

56 In order to provide an accurate geomorphic evaluation of the sediments, soil samples from the stratigraphic profiles are analyzed from the upper elevations of the trench, mid-trench

(within the boundaries of the cache feature), and along the lower elevations. In this, accurate dry and wet Munsell colors for each stratum can be obtained, as well as sediment texture, and levels of organic humus identified. Given the sloping environment of the excavation, sediment texture analysis from various portions of the profile may also elucidate lateral changes in the stratigraphy not readily visible in field settings, which can be important when evaluating potential catenary differentiation (Gerrard 1992:30-31).

Sediment texture analysis is initially performed using the Bouyoucos hydrometer method

(Bouyoucos 1936; 1962). In this method, the sediment sample is dried thoroughly with the initial weight recorded. The sample is then sieved to remove the greater than 2 mm fraction from the sediment matrix, of which the former is weighed to provide a percentage of material sizes larger than sand. Fifty grams of the remaining sediment is mixed with dispersing agent and lukewarm water (68° F), after which the sediment is allowed to settle. Hydrometer readings at 40 seconds and 2 hours will enable calculations of the percentage of sand and silt in the sample to be measured, respectively. After this time span, the only sediment left in the suspension will be clay. In order to separate out the coarseness of the sand component even further, additional sieve analysis is performed on the C-horizon sediment. Sieve sizes used for this analysis include: 1.18 mm, 0.6 mm, 0.3 mm, 0.212 mm, 0.15 mm, and 0.075 mm.

Testing for levels of organic humus in each stratum is performed utilizing the LaMotte

Company Instruction Manual (Model STH Series, 2001). This process requires 4 grams of sediment added to a soil extraction tube, followed by the addition of a demineralization solution and humus reagent powder, with intervening periods of thorough mixing. Once this is accomplished, soil flocculating reagent is added, the solution is mixed gently, and then allowed to settle for several minutes. The resulting mixture is then filtered into a second extraction tube.

57 The color of the filtrate is then compared to a color chart and the humus level can be related to a three-tier system of either low, medium, or high.

ARTIFACT AND FAUNAL REMAIN ANALYSIS

Due to the focus of this research, the only specialized analysis conducted on artifacts is protein residue. Recovered lithic and faunal remain materials are not expected to be of significant quantities and analysis is provided by the primary researcher of this project. Bone class and element, including left or right side, is identified as reliably as possible depending on the preservation level of each faunal remain recovered. Species are also categorized as accurately as possible, but highly fragmentary specimens may only be identified to a general size class (e.g. medium mammal) or not at all. Comparative faunal collections from previous investigations on the PCMS or Fort Carson are utilized as appropriate. In addition, evidence of cultural modification is noted.

Chipped-Stone Lithic Artifact Analysis

Any recovered lithic artifacts are analyzed based on the criteria outlined by Ahler (1997) and developed for New Mexico State University fieldwork at the PCMS. In the following paragraphs, a brief summary of pertinent artifact types is described with artifact analysis procedures introduced.

Analysis of chipped-stone debitage includes four major categories: size grade, material type, flake classification, and the presence or absence of cortex. Additional comments can include evidence of heat exposure or a carbonate coating, the condition of the platform, or the morphology of the flake termination. Chipped-stone debitage is defined as any knappable stone material containing evidence of intentional modification through the reduction of a parent piece or core nodule (Ahler 1989:129). The presence of a platform, bulb of percussion, recognizable dorsal and ventral surfaces, an eraillure scar, or ripple marks provides evidence of human initiated reduction. If none of these characteristics are noted and the specimen is composed of an irregular

58 and blocky shape, and is of a knappable material, it is classified as shatter (Andrefsky 1998). In many lithic reduction experimental studies, a large proportion of shatter specimens within a particular context can be a good indication of early hard-hammer lithic reduction stages with later stages of manufacture tending to exhibit lessening amounts and decreasing sizes (Ahler and

Christensen 1983:187). Size grades (large and small) are simply sorted in relation to a 1/2-inch screen, with smaller items passing through the screen in any orientation. Comparative collections, documented attributes, and knowledge of local outcroppings of knappable tool stone on the PCMS assist with the classification of the raw material utilized.

There are six major categories of debitage types: simple, complex, biface-thinning, shatter/debris, bipolar, and minute retouch. Simple flakes are defined as a free-hand percussion or pressure flake exhibiting two or fewer flake scars on the dorsal surface. In the absence of evidence for biface-thinning attributes, complex flakes are categorized as containing dorsal flake scars of three or more. Counts of flake scars should not include smaller scars associated with the platform, which are a reflection of platform isolation and preparation during the course of a single flake removal and are not a reflection of potential stage of reduction. Through the course of lithic reduction, there is a general trend where later stages exhibit smaller size grades, higher frequency and more closely spaced flake scar intervals, and a steady reduction in cortical surfaces

(Andrefsky 2004:205; Andrews and Greubel 2008:28-29; Callahan 2000; Root 2004:68). Cortex can be a weathering rind or the natural exterior surface of the raw material utilized.

A set of specific attributes can be used to classify a biface-thinning flake. As defined by

Ahler (1986), these characteristics include: (1) thin, flattened transverse cross-sections, (2) or thin, curved longitudinal cross-sections, (3) very acute lateral and distal edge angles with feather terminations, (4) several multi-directional dorsal flake scars, (5) narrow and typically faceted platforms, (6) platform lipping, (7) distal flake expansion, and (8) less defined bulbs of percussion. Overshot flakes may also be produced during biface reduction. These forms of

59 biface-thinning flakes exhibit evidence of flake removal that extends across the entire width of the biface removing a portion of the opposite margin (Huckell 2014:139).

Bipolar flakes are of a specialized reduction technique where an anvil is utilized for flake removal, in which the ventral surface exhibits evidence of opposing force scarring. Minute retouch flakes are of a small size grade and exhibit small, flattened or slightly curved cross- sections with feather or step/hinge distal terminations typically observed. These flake classes are typically associated with efforts to shape, (re-) sharpen, or refurbish stone tool edges or are an attempt to prepare and isolate platform surfaces for more controlled larger flake removals.

While not included in the Ahler system (1997), another flake type pertinent to this research is the blade flake. These types are produced from a prepared core (a large nucleus of stone) and prominent ridges are utilized to remove flake blanks. The resulting blade typically shows one or more ridges that extend the length of the flake and the length must be at least two- times the width. In addition, blade-like flakes contain all the attributes of a blade flake, but there is no other evidence to indicate that these flakes were produced by intentional blade technology from blade cores. They could have been produced through other reduction techniques and are thus not considered to be true blades (Collins 1999).

Chipped-stone tool classes can include (1) small, thin patterned bifaces, (2) large, thin patterned bifaces, (3) unfinished bifaces, (4) patterned tools, (5) retouched/utilized flakes, (6) large core or bifacial core tools, (7) non-bipolar cores, and (8) bipolar cores. Analysis of these tool types also includes size measurements (utilizing a caliper), raw material type, and the presence or absence of a cortical surface. Small and large bifaces exhibit uniform bifacial margins of which the tool has been heavily retouched and thinly shaped. Smaller forms may be hafted or unhafted and intended for use as a projectile associated with bow-and-arrow technology, while larger specimens may have been used to tip spears or darts. However, this is not to suggest that projectile points were the ultimate objective of these tool types and they may have been intended for other purposes (such as knives or chopping implements). Unfinished bifaces tend to

60 have uneven margins, higher width/thickness ratios, exhibit varying stages of reduction, or may have been abandoned during manufacture (due to breakage or unintended mistakes). These artifacts may have been intended for use as bifacial cores for the production of usable flake blanks or may have sufficient edges to perform needed tasks (Ahler 1986; Callahan 2000).

Patterned tools are shaped through secondary flake removal and retouch in order to produce an intended outline form, such as an end scraper or drill. Tool types within this broad class will be further subdivided in the laboratory according to shape and flaking attributes with an interpretation of tool function. Retouched/utilized flakes are tools of an expedient nature that contain minor retouch or utilization wear on one or more useable edges. These types are not shaped for a particular use, but the resultant flake morphology dictates whether the blank is suitable for a particular task. If these flakes are removed from prepared cores (such as blade or bifacial), the resultant flake shape and edge angles would be more predictable and likely beneficial for an intended utilization.

The large core tool/bifacial core tool class consists of any usable raw material that has evidence of utilization, either through retouch of various edges, battering wear, or bifacial manufacture. In regards to the latter, no retouch or use wear may be present, but this large tool could exhibit edges suitable for use as is and still maintain enough parent material for useable flake blanks to be removed.

Andrefsky (1998:80-81) defines a core as “a modified nucleus or mass of chippable stone rather than a tool with some particular type of function. The nucleus is not a recognizable flake nor is it a biface.” While bipolar cores contain flake scars that exhibit opposing bulbs of percussion, ripple marks, and flake terminations indicative of anvil use as a netherstone; non- bipolar cores simply contain multiple flake scars that may be removed in single or multiple directions.

61 CHAPTER IV

OWENS CACHE EXCAVATION RESULTS

OWENS CACHE LANDFORM

Taylor Canyon is a highly sinuous drainage system that flows generally from northwest to southeast. From a broader perspective, the site is located on the southwestern side of the canyon with the drainage maintaining a general southern direction at the cache location. The viewshed from the locale is limited due to the lower elevation and level of canyon incision, with an eastern to northeastern aspect (Figure 4.1). While the canyon is fairly deep at the site, the primary nickpoint is located a short distance downstream, where high canyon walls and water impoundments are more regularly observed. Local vegetation is of pinyon pine-juniper woodland with dense patches of one-seed juniper noted in the site area. Due to several areas of exposing bedrock, the understory is patchy with deeper deposits displaying fairly dense cover. Species identified include (but are not limited to) Bigelow’s sage, tree cholla, mountain mahogany, narrow-leaf yucca, prickly pear, broom snakeweed, buffalo grass, blue grama, common sunflower, and Russian thistle. While the quality of water resources can vary across this region, the unique sinuosity of Taylor Canyon and the creation of pond impoundments from mass wasting provide a more reliable and consistent water resource outside of the Purgatoire River. At the time of this investigation, there were only marginal pools directly downslope, but below the nickpoint to the east/southeast standing water was observed.

In general, the slope of the canyon at the site is gradual measuring from 6-12° with short distances of the slope exhibiting breaks of greater elevation change. These latter slope angles measure 25-39° along the upper elevation with a range of 13.5-18° on the lower (Figure 4.2).

These breaks are typically associated with exposing bedrock and represent structural terraces

(Gutierrez 2013:332) with the cache location itself exhibiting less weather resistant lithologies of shale and a thin-bedded sandstone underlying the dense blocky sandstone that comprises the

62 slight overhang of the rock crevice. Along steeper portions of the upper slope there is a break with a 25° inclination and no exposing bedrock. This may represent evidence of terracette development (Gutierrez 2013:248-249).

Figure 4.1. Owens Cache site overview (crew at cache feature).

Figure 4.2. Slope profile of western Taylor Canyon, A-F designations denote slope positions with rock lithology attributes documented (see Table 4.1).

63 Based on slope morphology and attributes, the cache assemblage lies on the lower portion of the colluvial footslope where redeposition of materials from the steeper slope above is occurring, as well as erosional processes such as creep and surface wash (Gerrard 1992:17-28).

Due to the presence of structural terraces along this lower, more gradual slope gradient, these portions are also susceptible to low magnitude mass wasting slump events. Approximately 4 m below the elevation of the cache, there is a large outcropping of white Dakota Sandstone with a sheer cliff face of approximately 2.2 m. This exposure becomes buried again, only a short distance from the thalweg and floodplain deposits are minimal along this side of the canyon due to the upstream location of the outer curve of the meandering channel. The opposite side displays a relatively broad floodplain with evidence of deeper deposits.

While the slopes above and below the cache location exhibit channer to boulder size sandstone rock fragments with largely angular edges; the lower gradient slopes of the cache area contain remnants of distinctly different lithology (Table 4.1). These include common occurrences of Thatcher Limestone and more limited instances of quartz gravels and cobbles. Some of these materials exhibit angular to sub-angular edges, but this appears to be a result of freeze-thaw fracturing after deposition. The former outcrops along the upper steppes (Schuldenrein 1985) with the quartz likely originating from Pleistocene outwash deposits along higher elevations (i.e.

McFaul and Reider 1990). In addition, Dakota Sandstone gravels are also noted that exhibited rounded to well-rounded edges, indicative of longer transport distances. Many of the upper reaches of Burke Arroyo, a headwater tributary to Taylor, exhibit extensive Dakota Sandstone exposures. Therefore, these materials appear to represent remnant coarse bedload clasts from fluvial processes prior to terrace abandonment and deeper channel incision in this portion of the canyon (Ritter et al. 2011).

From a surface perspective, soils appear to be shallow in general with areas of potential depth derived from colluvium or slope alluvium. From the structural terrace of the cache, there is more common bedrock outcropping exposures noted downslope, indicating a more pronounced

64 depositional environment derived from residuum with minor additions from aeolian or small scale slumping events (colluvial) possible. Upslope from the cache, a more convex slope shape is represented, suggesting deeper deposits derived from transportation of colluvial and slope alluvium materials. According to soil survey data (University of California-Davis SoilWeb

2018), the site area is composed of Travessilla-Rock outcrop complex with shallow Travessilla series entisols (55%) and rock outcrops (35%) comprising the majority. Other soil types commonly associated with these environments include Midway series (5%) and a deeper aridisol

(Ustic Haplocalcid – 10%). Based on the depositional attributes of the cache, a shallow

Travessilla series entisol association is likely represented.

Table 4.1. Rock fragment lithology, size, and roundness (see Figure 4.2 for slope position).

SITE OVERVIEW

The Owens Cache site (5LA12616) is a large open lithic scatter that exhibits a widely dispersed surface artifact assemblage with bedrock metate and rock art features also represented

65 (Owens 2015a; Owens et al. 2012; Owens et al. 2010). During the 2010 recording of the site, only two potentially diagnostic projectile points were recovered, which include a Hanna/Duncan variant (FS 12) typically associated with the Middle Archaic period, and an unstemmed, triangular point fragment (FS 27) commonly affiliated with the Late Prehistoric stage. These artifacts alone may represent multiple occupations or later groups may have curated the older projectile. The diagnostics are not directly related to the cache and are located either on the higher slope or exhibit considerable spatial distance (Figure 4.3). Analysis of the surface assemblage, which measures 145 x 70 m (6,151.57 m2 or 66,215 ft2), revealed additional Alibates chert artifacts. While the dispersed nature of the remainder of the Alibates specimens (N = 4) may indicate a broader utilization of the landscape by the people who left the cache, these materials are sparse and are associated with a potential multi-component surface assemblage.

The other features identified in 2010 were found in the area of the cache and are concentrated towards the southern end of the site. These include a bedrock metate use surface

(Feature 2) and one or two rock art panels. One of the rock art panels is on a small boulder containing pecked curvilinear abstract elements (Feature 4). However, the exact shape of these motifs are masked by weathering (rock coating exfoliation) of the boulder surface. The other rock art panel (Feature 3) consists of 25 sandstone channer fragments exhibiting lines that may form a geometric design. Debate over this panel continues, as the represented lines may be from natural phenomena rather than cultural modification.

Artifacts from the cache (Feature 1) were originally identified within a 2.0 x 0.7 m area below a sandstone exposure (Owens 2015a:129). These materials appeared to have been exposed by a partial collapse of the covering bedrock ledge with large boulder detachments and slumping identified (Figure 4.4). Based on a visual comparison, one of the boulder outlines could be directly correlated with a fractured portion of the sandstone exposure, which now lies 1 m down the slope (Owens 2015a:130). Many of the artifacts were found in direct association with these boulders or scattered in the immediate vicinity. A total of eight artifacts were recovered from the

66 surface. These included three flake tools, two disto-lateral scrapers, two bifaces, and one side scraper. The bifaces exhibited at least one overshot flake removal with two tools being used or shaped from blade-like flake blanks. Three additional tools also appear to be modified from larger biface-thinning flakes and radial fracturing of several of the tools was also documented

(Owens 2015a:132-133).

Figure 4.3. Owens Cache (5LA12616) site map.

67 Figure 4.4. Overview of cache feature.

In addition to the cache artifacts, there is a large tabular stone with dimensions of 52 x 26 x 6 cm lying on the edge of the sandstone exposure above the artifacts. The margins of this stone appear to be flaked and may represent a marker utilized to facilitate relocation of the cache materials (Figure 4.5). The parent material of this rock exhibits attributes of Pajarito Formation

Sandstone, which stratigraphically overlies the Mesa Rica Sandstone outcroppings of the site locale (Evanoff 1998). The nearest exposure lies 25 m away from the site and no other rock fragments of comparable size are observed at the locale that would indicate natural transport of this particular lithology. This seems to suggest that the stone was intentionally placed; however the modification of the stone edges has been questioned in regards to a human or natural cause

(Owens 2015a:131).

CACHE EXCAVATION RESULTS

Excavation was conducted during the late fall of 2017. A total of four excavation units (1 m blocks) were placed to bisect the cache. Excavation Unit 1 was initially established at the edge of the sandstone exposure and encompassing the detached boulder where the densest concentration of surface artifacts was identified. Additional excavation units were established

68 downslope and sequentially numbered XU-2 to XU-6, to include the trench extension. Since surface artifacts included within the cache were found near the XU-3 boundary, this unit was initially excavated according to the methodology outlined for the cache interior until ample evidence was produced to indicate a lack of intact cultural remains. Subsequent waterscreening showed completely sterile deposits. Excavation Units 7-9 were placed along the upper ledge with

XU-7 bordering XU-1. Given the fact that XU-8 contained the cache marker, both XU-7 and 8 were considered within the cache boundaries. Due to time constraints and the large window already provided by XUs 1-4 and 7-8 for geomorphic interpretation, excavation of XU-5, 6, and 9 were not initiated and were left for potential future investigations. Subdatums were established along the upper, middle, and lower portions of the trench with string elevations tied into the primary site datum by total station measurements. Due to the sloping topography, elevation data for recovered materials will be reported based on the primary datum elevation in order to avoid confusion and maintain consistency throughout. In the following paragraphs, the depositional history of the cache will be described as well as a brief review of the artifacts recovered in regards to provenience. This will be followed by a more in depth description of the identified cultural materials.

Figure 4.5. Potential cache marker.

69 DEPOSITIONAL HISTORY

A total of three different strata were identified during the course of the trench excavation.

The primary strata included an A-horizon (Stratum II) and lower C-horizon (Stratum I) (Figure

4.6). Underlying parent materials include quartzitic blocky sandstone separated by interbedded shale and thin-bedded sandstone bedrock. While Stratum III exhibited the same basic C-horizon characteristics identified through the trench as a whole, this deposit displayed subtle differences.

These included the identification of common rusty-orange concretions and a notable decrease in silt content, which are likely a product of the location of the deposit underneath the slight overhang of the rock crevice (Figure 4.7). However, these subtle differences appear to be gradual, as no visible facies change could be identified along the overhang edge. Similarly, no vertical soil boundaries were observed between the upper and lower excavation units, indicating marginal influences from catenary differentiation. Milne (1936; cited in Gerrard 1992:30) defines catenary differentiation as a result of slope processes where finer grained materials and more mobile elements (depending on drainage conditions) are leached and collect into downslope positions where distinct facies or lateral soil divisions develop. Laboratory soil analysis revealed slight differences in color and texture, but these appear to be due to subtle variations in elemental composition (USDA 2018a) with textural changes being so minimal that soil classes only varied between sandy loam to loamy sand designations, with most lying near the boundary of these classes (Table 4.2).

While the LiDAR scan of the open trench and the surrounding area did not reveal any key landform attributes that were not readily visible during the field investigations, the resulting three-dimensional imagery did provide excellent representations of the excavation area and the cache feature (Figures 4.8 - 4.10). These results are not too surprising given the overall lack of vegetation throughout the landform, especially in the immediate area surrounding the feature.

70 Figure 4.6. Trench stratigraphy of cache at 5LA12616.

71 Figure 4.7. North wall stratigraphy of Excavation Units 1, 2, and 7.

Table 4.2. Soil analysis data for trench stratigraphy (* denotes sediment under overhang).

72 Figure 4.8. LiDAR scan imagery of trench excavation and cache feature, contoured planview with black lines representing 10 cm intervals and gray 0.5 cm intervals.

Figure 4.9. LiDAR scan imagery of trench excavation and cache feature, angled representation showing the main cache area and northern trench side walls.

Stratum I lies above decomposing shale and sandstone bedrock and consists of the C- horizon of a poorly developed entisol. Due to the undulating nature of the underlying bedrock and the weathering-limited environment (Gerrard 1992:15-16), there is a highly variable stratum thickness of 3.5 to 23 cm. The sediment is of a very pale brown to light gray (dry) and brown to

73 yellowish brown (moist) fine sandy loam. Soil structure is consistently represented as weak to moderate sub-angular blocky with a slightly hard (dry) to friable (moist) consistence. Slight differences in the latter were noted in XU-4, at the downslope end of the trench, with soft (dry) and very friable (moist) attributes documented. Humic levels, as expected for a C-horizon, were low to very low. The matrix varied in rock fragment volume from 9% in the upper slope C- horizon of XU-8 to 25-27% for the lower slope contexts. Volumes were calculated based on the dry weight to volume conversion chart provided by the Natural Resources Conservation Service

(USDA 2018b). Rock fragments were primarily composed of various sized sandstone channers in the lower slope contexts (99%) with thin-bedded sandstone (70%) dominating in XU-8. Sparse fine to coarse sandstone gravels exhibiting sub-rounded to rounded edges were also documented with Thatcher Limestone only represented by a single medium gravel. Dilute hydrochloric acid tests on the soil were highly effervescent. The inference of high carbonate levels in this soil horizon was also observed during humic level tests, when mixing of the humus screening reagent powder created considerable pressure and off gassing. Lower boundaries with bedrock were very abrupt and wavy.

Figure 4.10. LiDAR scan imagery of trench excavation and cache feature, close-up of main cache area.

74 Cultural materials from this stratum were sparse with the majority associated with the upper A-horizon contact. When artifacts were found in deeper levels within the C-horizon, these materials were directly associated with the lower boundary of the depression created by the detached boulder and appear to have been displaced by the collapse. Artifacts consisted of microdebitage specimens and a potential culturally introduced claystone fragment. However, debitage recovered from XU-8 stood in stark contrast to this pattern with two specimens recovered from deeper levels that corresponded to this stratum. With the exception of gastropods, no faunal remains were identified. Gastropods are found in higher concentrations near the sandstone exposure, which is likely related to longer periods of higher moisture content.

Especially downslope from the overhang, gastropods were regularly identified even in this lower stratum.

Stratum II is the A-horizon and it is comprised of a brown to grayish brown (dry) and dark brown to very dark grayish brown (moist) fine sandy loam. Within XU-1, a slight reduction in silt and clay is noted that corresponds with a loamy sand designation. Thickness fluctuates from 3.5 to 22 cm. Soil structure varies from a granular aggregate to moderate sub-angular blocky with a soft (dry) and very friable (moist) consistence. While the upper slope (XU-8) A- horizon exhibited low humic content comparatively, more moderate levels were noted through the majority of the trench. The matrix varied in rock fragment volume from 13 to 40% (USDA

2018b). Rock fragments were primarily comprised of various sized sandstone channers with sparse Thatcher Limestone fine to coarse gravels comprising approximately 1-3% of the samples.

Additional fine to coarse sandstone gravels (very sparse) were also recovered that exhibited rounded to well-rounded edges. Dilute hydrochloric acid tests on the soil were highly effervescent with the same significant off gassing observed during humic level tests. All lower boundaries with the C-horizon were clear and either smooth or wavy.

Cultural materials outside of the overhang are generally associated with this upper surface stratum and are comprised primarily of microdebitage specimens. Of the 23 debitage

75 specimens identified, 19 were located within XU-1 and immediately downslope within XU-2, providing a direct correlation with the bedrock exposure and the overhang (Figure 4.11). Located just outside the overhang within XU-1, a stone tool (FS 127) was recovered within the first 2 cm of the ground surface and mapped in place (Figure 4.12). The sediments in this area show a gradual change from the surface A-horizon to the slightly different microclimate attributes underneath the overhang. Sparse faunal remains (N = 2) were also identified, but appear to be intrusive small animal species with no evidence of cultural modification. Gastropods were regularly encountered in these contexts.

Figure 4.11. Planview map of cache feature showing artifact distributions and stone tool locations.

76 Figure 4.12. Location of Field Specimen 127 in relation to the overhang.

Just downslope from the bedrock exposure and buried within the A-horizon of XU-2, there is also evidence of the partial collapse of the sandstone ledge, as well as the possible composition of the ground surface prior to this event. In regard to the collapse, there is a distinct increase in the total weight of sandstone rock fragments starting at 2.72 m below the primary datum elevation. In the levels above this, the average weight of sandstone recovered is measured at 1.84 kg with the levels below this exhibiting an average weight of 5.81 kg. These lower levels are also associated with the majority of the collected debitage from XU-2, a .50-caliber bullet, and three cryptobiotic or biological soil crust remnants (Figure 4.13). Sandstone fragment weights correspondingly decrease at 2.82 m below the datum elevation with weights ranging from

0.65 to 1.21 kg. While the larger boulders of the collapse can be viewed from the surface, this 10 cm interval exhibits drastic increases in blocky, quartzitic sandstone fragments that appear to represent the smaller clasts from this event.

Figure 4.13. Biological soil crust remnants recovered from XU-2.

According to Belnap (2003:181), a biological soil crust “refers to the cohesiveness of the soil surface created by soil crust organisms.” While these crust surfaces are seen sporadically in portions of the PCMS, there was no visible evidence of this on the modern ground surface of the cache or throughout the broader landscape of this area at the time of the investigation.

Identification of these remnant fragments buried within the A-horizon of the XU-2 deposits and their potential relationship with the sandstone ledge collapse, suggests that the soil surface supported these organisms prior to this event. However, with the location of only a few fragments, it is difficult to assess the possible extent that the crust covered the surface. Biological soil crusts not only form under relatively stable soil conditions, they also provide a protective layer that subdues water and wind erosion (Belnap 2003:183-184). In addition, the rough texture and “sticky” surfaces of a biological crust attract nutrient-rich dust and can aide (albeit minimally) in aeolian deposition. Many of the debitage specimens were also found in association, which may indicate a surface context for these materials prior to the collapse event.

78 While biological crusts are certainly stabilizing influences for the soil matrix, Belnap (2003:184) stresses that elevated moisture retention and an increase in freeze-thaw actions are also demonstrated, which have shown to increase the rate of bedrock weathering by as much as 100 times. Whether this contributed to the collapse at the site cannot be said with any certainty, but the presence and potential impacts of a biological crust is important to note.

An intrusive cultural material was also documented within these XU-2 A-horizon levels.

It consists of a .50-caliber bullet with a slightly mushroomed end (Figure 4.14), of which the latter may have been produced by striking bedrock or a smaller rock fragment near the cache feature. There have been no known live-fire training exercises conducted within this portion of the PCMS since the base was established. However, cultural resource inventories at the installation have identified several .50-caliber shell casings that are consistently observed within or nearby the more deeply incised canyon settings (e.g. Swan et al. 2012). Headstamps on these casings clearly indicate a World War-II date range, during which time the United States Army Air

Corps was conducting training from a La Junta airfield and firing .50-caliber machine gun rounds from aerial platforms. This artifact appears to be from these training exercises. Whether this influenced the collapse of the ledge or not is entirely speculative.

Figure 4.14. .50 caliber bullet recovered during excavation.

79 Stratum III is the C-horizon sediment underneath the slight overhang of the sandstone exposure. Organic humus are present in low levels with some materials from the A-horizon likely being leached into these sediments, of which Stratum II bordered and partially buried the bedrock edge. Due to differences in moisture retention under this rock, slight changes in soil attributes were noted in comparison to the surrounding sediment. These included common occurrences of rusty-orange concretions, lower silt content, as well as evidence of insect chitin and pupae fragments. As a result of erosion or disturbances, some of these materials were identified in the surrounding strata in sparse numbers. Since cultural materials were identified in primary context under this overhang, the sediment was pedestalled with samples collected separately and subjected to specialized analysis. These included elemental composition of the sediment and concretions (X-ray fluorescence [XRF]), identification of macrobotanical and charcoal remains, and AMS dating (Scott-Cummings et al. 2018).

This sediment consists of a pale brown (dry) to dark grayish brown (moist) loamy sand, which exhibits a layer thickness of 9 to 25 cm relative to the undulating boundaries of the underlying bedrock. Elemental analysis of this sediment showed higher concentrations of silicon

(23.17-25.52%), calcium (6.7-8.17%), and aluminum (6.12-6.6%) with iron (1.57-1.76%), potassium (1.19-1.28%), and magnesium (0.47-1.07%) noted in smaller quantities. Additional elements measuring less than 1% include sodium, phosphorus, sulfur, titanium, and barium. Soil structure varies from granular to weak sub-angular blocky with a soft (dry) and very friable (wet) consistence documented. Rock fragment volume measured 27% with thin-bedded sandstone comprising the majority (approximately 70%). No Thatcher Limestone or quartz gravels were observed. However, fine to medium sandstone gravels with sub-rounded to rounded edges were documented. Dilute hydrochloric acid tests on the soil were highly effervescent with the same significant off gassing observed during humic level tests. The lower boundary is very abrupt and wavy.

80 While cultural materials were sparse under the overhang, these remains consisted of two stone tools identified in primary context (Figure 4.15 and 4.16). Field Specimen 158 lied along the southern edge of the overhang, just below the thin-bedded sandstone exposure at the back wall. Similarly, FS 178 was found on the opposite northeastern edge with a slightly higher provenience elevation (Figure 4.17). No microdebitage was identified under the overhang. With the exception of insect chitin fragments and gastropods, faunal remains were sparse with only one small animal mandible fragment recovered.

Figure 4.15. Field Specimen 158 location under overhang.

81 Figure 4.16. Field Specimen 178 location under overhang.

Figure 4.17. Cache planview showing stone tool locations in relation to overhang and bedrock exposures.

82 Sediment samples sent for specialized analysis to PaleoResearch Institute were directly associated with the lower level of the stone tools recovered and slightly below (2.40-2.43 m [FS

174] and 2.43-2.46 m [FS 176] below the primary datum). Macrobotanical remains within the overhang deposits included uncharred seeds, leaf, and cones indicative of juniper, sage, goosefoot, and spurge vegetation in the feature area. Identified charcoal was comprised of smaller fragments that could only be classified as conifer along with larger specimens of juniper.

Accelerator Mass Spectrometry (AMS) dating of the charcoal within both samples produced two nearly identical dates of 313 ± 21 radiocarbon years before present (RCYBP) and 318 ± 21

RCYBP, which corresponds to the Protohistoric period of the Late Prehistoric stage (Scott-

Cummings et al. 2018).

In addition, the common occurrence of rusty-orange concretions (Figure 4.18) within the overhang sediment was evaluated in relation to source. As can be seen in many of the figures above, a juniper stump (13.2 cm in diameter) and root system lies just outside the overhang with one of the larger roots penetrating the lower sediments under the ledge. The exterior of these roots are largely rotted with many of these wood fragments cemented within the concretions. X- ray fluorescence (XRF) of these specimens revealed that the majority of the elements were not measureable by the XRF. However, elevated levels of bromine seem to support a largely organic composition. Measureable elements included silicon (6.26%), calcium (4.87%), and aluminum

(2.21%) with minimal amounts (less than 1%) of sodium, phosphorus, sulfur, potassium, titanium, barium, and iron also identified (Scott-Cummings et al. 2018). According to Fairbridge and Bourgeois (1978), concretions often form around the nucleus of a dead organism, which is followed by concretion enlargement due to bacterial decay of organic matter. Therefore, it appears that these concretions formed within the larger and smaller root channels of the overhang and are biogenic in origin.

Figure 4.18. Organic concretions identified under overhang (lower left concretion with rotted root fragment).

CARBONATE COATINGS AND OXIDATION ON ROCK FRAGMENTS

Soil analysis showed that the sediment matrix in all strata contained significant levels of unprecipitated carbonates with XRF analysis under the overhang revealing calcium levels of

6.17-8.17%. Carbonates in soils can be from a variety of sources to include landform parent material, dust, and rain. In order to assess the source of the carbonates at the site, a more detailed study focusing on petrographic analysis of the parent rock, as well as regional dust and rain contributions would have to be conducted, as these various sources can fluctuate widely across different regions (Chadwick and Graham 2000:E-54 – E-55). However, given the marine environment associated with the Dakota Group Shale and Sandstones, higher calcium carbonate levels from the local parent material are commonly inferred (Evanoff 1998; Boggs, Jr. 2003).

These high levels of calcium carbonate are also represented on the rock fragments of this landform, as witnessed either from excavation or on the surface (Figure 4.19). Measureable carbonate coatings on coarse sandstone rocks varied from as low as 1.43 mm or less to as thick as

84 10.15 mm. Additional calcrete specimens containing one flat surface, indicative of rock detachment, exhibited thicknesses as high as 24.78 mm. Often the precipitation of carbonates is more pronounced on the undersides of rocks, as water tends to collect and dry more slowly.

Furthermore, once calcite crystals start to accumulate on a rock surface, this coating will thicken over time, as “calcite is preferentially precipitated on preexisting calcite crystals” (Chadwick and

Graham 2000:E-56).

Figure 4.19. Rock fragments with carbonate coatings and calcrete recovered during excavation.

Given the shallow soil depths associated with the weakly developed A/C-horizons identified in the excavation, as well as the younger dates for the overhang deposit, there is little opportunity for vertical pedogenic calcium carbonate precipitation and accumulation. However, slope processes and run-off within this environment, which continually erodes the sediments,

85 seems to be also contributing to calcium carbonate coating development on the larger clasts.

While Pustovoytov (2003:136) was conducting research based on vertical pedogenic processes, the results produced widely varying rates of coating thickness development in different semi-arid environmental settings. These rates fluctuated from 1 to 5 mm per 1,000 years. With calcrete thicknesses as high as 24.78 mm at the site, it seems that several of these rock fragments have not been subject to high enough erosional events to remove them from the landscape, which has allowed thick carbonate coatings to develop over a substantial period of time.

In addition, several rock fragments exhibited evidence of oxidation with sizes varying from small to large channer (95 mm). These specimens were very sparse and scattered throughout the trench excavation with no patterning or concentrations indicated. If this oxidation was a product of cultural use, these materials have been so heavily displaced that no potential features (i.e. hearth) can be inferred.

CULTURAL MATERIALS FROM EXCAVATION

Cache artifacts recovered during excavation included three stone tools and 23 pieces of microdebitage. An additional claystone fragment was also recovered. This latter item did not exhibit evidence of cultural modification. However, there is no evidence for the natural occurrence of this lithology across the site area and known quarries of this material are located closer to the Purgatoire River and within the deeper portions of these canyon settings (e.g. Swan et al. 2012). This presents the possibility that this item was culturally placed, perhaps with the intention of future shaping.

The recovered stone tools exhibit material types and technological attributes like those documented during the 2010 site recording (Table 4-3). Field Specimen 127 was manufactured from Alibates chert and exhibits attributes that indicate a multi-purpose flake tool function

(Figure 4.20). Based on the lipped platform and cross-section curvature, this item represents a large biface-thinning flake blank with subsequent modification for tool use. The proximal ends

86 of both lateral edges contain higher edge angles (49-74°) with dorsal surface patterned retouch and closely spaced flake scar intervals observed. Only sporadic micro-step/hinge fractures were noted along these surfaces to indicate scraper use. However, retouch and re-sharpening may have obliterated more substantial use wear evidence. In contrast, the medial and distal lateral edges exhibit angles ranging from 31-54° with bifacial edge rounding and micro-step fractures suggestive of use as a cutting implement. This use wear was heaviest along the right lateral side.

Additional retouch along the extreme distal termination of the tool is also noted with the possible intention of forming a crude point for use as a perforator.

Table 4.3. Summary data for recovered stone tools.

Field Specimen 158 is a long, narrow blade-like flake with dorsal surface retouch and use wear noted on both lateral edges and the distal end (Figure 4.21). Larger retouch flakes with a narrow scar interval are more prevalent on the proximal end of the lateral edges with multiple micro-step/hinge fractures and significant edge rounding observed. The distal end of the tool shows more minimal patterned retouch with isolated concentrations of micro-step/hinge fractures and no observable edge rounding. Edge angles measure from 55-85° and are indicative of a scraper function. Residue analysis on this artifact was positive for the presence of canine

87 proteins, suggesting this tool was potentially used to process coyote, wolf, fox, or domestic dog species (Scott-Cummings et al. 2018).

Figure 4.20. Field Specimen 127 of the Owens Cache.

Figure 4.21. Field Specimen 158 of the Owens Cache.

88 Field Specimen 178 is a large stone tool exhibiting highly patterned and narrow flake scar intervals along both lateral edges from extensive shaping and potential re-sharpening modifications (Figure 4.22). The tool stone is a dendritic chert of high quality with a mottled and slightly banded white, tan, and brown coloring. Small branching dendrites are present in concentrated areas along both the ventral and dorsal faces. Little evidence of use wear was noted on the lateral edges, which may be indicative of re-sharpening prior to storage in the cache.

While the distal end does not show evidence of edge shaping and patterned retouch, there is significant use wear in the form of edge rounding and a high polish. Edge angles measure 55-75° and the attributes of this tool are indicative of a scraper function, of which the lateral sides are more formalized. Due to a small snap fractured corner, the width measurement in Table 4.3 is slightly smaller than the actual dimension. Residue analysis on this artifact was positive for

Cervidae proteins, which may indicate use for processing deer, elk, or possibly moose. However, the underlying sediment also tested positive and the origin of these proteins may not be from the tool itself (Scott-Cummings et al. 2018).

Figure 4.22. Field Specimen 178 of the Owens Cache.

89 Chipped-stone debitage were all of small size grades and included 15 minute retouch flakes, six shatter or angular debris fragments, one simple flake, and one complex flake (Table

4.4). Due to the size of these specimens, material types were more difficult to establish and were only classified to a more specific source location if definable attributes could be discerned. Nine specimens could be reliably categorized as Alibates chert with the remainder of the chert specimens (N = 12) displaying a wide variety of colors as well as opaque or translucent properties. Silicified wood and chalcedony (one each) material types were also documented.

Given debitage attributes, late-stage lithic reduction focused towards shaping and (re-) sharpening of tool edges as well as potential platform preparation activities can be inferred. In addition, there is the potential that a wider variety of tool stone sources were utilized than is currently represented by the cache tools alone. This may indicate the presence of additional tools in buried context or the manufacture of tools at the site, which were utilized and subsequently discarded or stored elsewhere.

Table 4.4. Debitage summary data for the Owens Cache.

90 Table 4.4. Debitage summary data for the Owens Cache (continued).

FAUNAL REMAINS

The faunal remains recovered during excavation are primarily composed of fresh water mollusks with only sparse vertebrate species identified (N = 3). While these specimens were not sent for specialized analysis, several of the bone fragments exhibited very specific attributes that allowed for reasonably accurate identification by the primary investigator. This was not only accomplished through previous experience in faunal analysis work, but also from high-resolution comparative photographs presented in Walker (2008). Gastropod identification could also be partially accomplished with specimens presented in Walker (2008) with Nekola and Coles (2010) helping with potential pupilliform species correlation. In this analysis, gastropod attributes such

91 as shell type, aperture size and shape, whorl counts, and spire morphology were compared to known species of the Central and Southern Plains in order to provide as accurate an assessment as possible for family, genus, or potential species identification. If future paleoenvironmental research finds these specimens to be of use, all varieties of these gastropods will be curated for verification of these findings.

Two of the three vertebrate bone fragments could be identified according to genus and possibly species (Figure 4.23). Both of these consisted of left mandible elements of which the size, morphology, and tooth pattern were directly comparable to Sceloporus sp. (fence lizard) and

Reithrodontomys sp. (harvest mouse). In regard to the former, all attributes compare very favorably with Sceloporus undulatus or the eastern fence lizard. The other faunal remain was too fragmentary for identification, but it did appear to represent a small mammal species. No evidence of cultural modification was observed and these remains appear to be unrelated to the cultural component.

Figure 4.23. Faunal remains recovered from excavation, (a) left mandible similar to Sceloporus sp. (fence lizard), (b) left mandible similar to Reithrodontomys sp. (harvest mouse), (c) unidentified bone fragment.

92 Gastropod characteristics could be reliably identified to family or genus; however, species identification is difficult to determine without a comparative collection. In some cases, soft tissue anatomy is required in order to separate taxon (Walker 2008), which would not be feasible with these specimens. Figure 4.24 shows a representative sample of the types of gastropods recovered during excavation, which are similar to Family Succinidae (amber snail),

Vallonia sp., and Pupoides sp. shell forms. As expected, the majority of the snail shells were found in close association with the overhang, with 222 of the 240 specimens found within XU-1,

2, and 7 contexts. All varieties of gastropod recovered are either known to have a wide range of habitats or are drought tolerant, making these specimens relatively poor proxies for paleoenvironmental reconstruction. No living snails were identified during this investigation with overall dry conditions documented under the overhang.

Figure 4.24. Representative gastropods recovered from excavation, similar to known Central and Southern Plains specimens of (a) Family Succinidea (amber snail), (b) Pupoides sp. (cf. Pupoides abilabris [white-lipped dagger]), (c) Pupoides sp. (cf. Pupoides inornatus [Rocky Mountain dagger]), (d) Vallonia sp.

93 CHAPTER V

CONCLUSIONS

Investigation of the Owens Cache has demonstrated that an intact component lies beneath the ledge of the sandstone exposure. Accelerator Mass Spectrometry dating of charcoal recovered from the deposits under the overhang and from the same level (and slightly below) as the stone tool artifacts found within primary context, provided two nearly identical dates of 313 ±

21 and 318 ± 21 RCYBP. These data indicate that the cache assemblage is associated with a later

Protohistoric period use, rather than a Paleoindian affiliation as proposed from previous studies

(Owens 2015a). Based on research by LaBelle (2015), this feature appears to be the only confidently dated cache assemblage of the Protohistoric period discovered thus far in Colorado.

From a broader landscape perspective, the unique attributes of Taylor Canyon and its position in relation to the Hogback likely facilitated the potential relocation of the cache materials. In contrast to the other canyons, Taylor exhibits high cliff faces and a narrow stream channel conducive to large mass wasting events and the creation of natural water impoundments, of which these water sources show significant time depth based on geomorphological investigations of the floodplain stratigraphy (Schuldenrein 1985). This not only places the cache within an area of potentially rich natural resources, but also within an area conducive to relocation of the stored assemblage. The potential cache marker may have served as a more localized indicator of the specific cache location.

Based on landform attributes, along with the stratigraphy and bedrock composition exposed within the trench excavation, a geomorphic interpretation of the cache location can be analyzed. The sandstone ledge of the cache represents a structural terrace located along the western, lower colluvial footslope of Taylor Canyon. Slope orientation and shape characteristics indicate that this structural terrace serves as a break in slope processes with deeper deposits of colluvium and slope alluvium noted upslope. The sediments below this are primarily shallow residuum with the collapse of the bedrock ledge providing a more localized colluvial addition.

94 The stratigraphy bears this out with the deposits varying from 5.6 to 34.75 cm thick depending on the undulating morphology of the underlying bedrock (Figure 5.1). Weak soil development is seen throughout the trench with the A/C-horizons of an entisol identified, which exhibit characteristics of the Travessilla series (UC Davis 2018). While slope processes are consistently eroding the sediments of the slope, these do not appear to have been of sufficient energy to remove many of the larger rock fragments. The latter exhibit either thick carbonate coatings or represent bedload materials prior to fluvial terrace abandonment and drainage incision. This suggests time depth for these rock fragments with lower energy erosional forces dispersing these materials broadly across the local landform. However, this does not indicate that the cache assemblage might be of an older age. These stone tools were concentrated within a discrete depositional unit under the overhang with two solid corroborating AMS dates.

Weathering of less resistant thin-bedded sandstone and shale under the blocky, quartzitic sandstone of the ledge provided a small crevice for the storage of the cache. Based on the extent of these underlying lithologies, the dimensions of this crevice within the wall profile are 49 cm in width and 13.5 cm in depth. Prior to the collapse, the larger sizes of the detached boulders (100 x

68 cm and 119 x 63 cm) may have extended these dimensions slightly. However, the fractured back edges of the ledge are covered by sediment and would need to be exposed in order to provide more concrete data regarding the potential width dimensions of the overall feature. The length dimension of the cache is impossible to determine due to the collapse and downslope displacement of most of the known assemblage. Field Specimen 178 was identified in the northern sidewall of XU-1 and there is potential for more intact portions of the cache assemblage that remain undiscovered. The recovery of biological soil crust remnants within the matrix of the boulder collapse materials suggests a stable landform prior to this event. The extent of this crust is unknown as well as the level of potential affect it had upon increased weathering rates of the sandstone ledge. In addition, the presence of a juniper stump directly outside the overhang, likely helped to protect the deposits, but also may have contributed to the collapse due to root

95 penetration. Macrobotanical remains within the overhang deposits indicate an ecosystem comparable to the present with juniper, goosefoot, sage, and spurge vegetal elements identified.

While these were not charred to indicate cultural use, it is interesting to note that goosefoot seeds are more frequent, which has been shown to be a valuable economic species through a broad span of prehistory (e.g. Swan 2009).

Figure 5.1. Overview of Owens Cache landform post-excavation.

When the artifacts recovered from the cache excavation are added to the 2010 materials, the assemblage includes a total of 35 artifacts with 11 stone tools, 23 pieces of debitage, and a potential claystone manuport comprising the known contents. Debitage flake types and raw materials indicate (1) a focus towards late-stage reduction with tool shaping and

(re-) sharpening activities; and (2) tool manufacture from a more diverse range of raw material sources than is currently represented by the tool assemblage. The latter may indicate the presence of additional tools in the cache or the occupants used these other tools and subsequently stored or discarded the items elsewhere. Both stone tools recovered from under the overhang tested positive during residue analysis with canine (e.g. wolf, fox, coyote, domestic dog) and cervidae

96 (e.g. deer, elk, moose) proteins identified on FS 158 and FS 178, respectively. The presence of cervidae proteins in the soil underlying FS 178 has led to questions regarding a natural or cultural origin. However, the placement of this artifact within the rock crevice seems to support a cultural introduction, perhaps representing trace elements of heavily deteriorated organic gear.

The stone tools represent a continuation of the material types and technological attributes identified from the surface collected remains. Functional classes include five flake tools, two disto-lateral scrapers, two side scrapers, and two bifaces. Three items display modifications from blade-like flake blanks and four consist of large, broad biface-thinning flakes that may represent overshot removals. As discussed in Owens (2015a:132), the bifaces display evidence of at least one overshot removal. Most of these items are manufactured from exotic materials with Alibates chert dominating the tool assemblage. The dendritic chert specimen (FS 178) is of a high quality material of an unknown source. However, there are no known quarries in the region that display the attributes of this raw material. Given the low raw material diversity of the tools, as well as the high utility and functional flexibility of these items, this cache appears to represent a utilitarian insurance cache as proposed by Owens (2015a:134). While most caches are placed with the intent of future recovery and utilization there is evidence at sites, such as 5AH3217

(Gilmore 2015), where the cache contents show no evidence of subsequent utilization or replenishment of the contents with recently procured tool stone. While the Owens Cache is difficult to interpret in regard to function as a continuance or discontinuance assemblage, the evidence seems to suggest the former. The presence of dendritic chert and Niobrara jasper, along with the predominant Alibates chert specimens, seems to indicate a return visit to the locale with the placement of raw materials from varying source locations. Although the debitage are sparsely represented due to the limited extent of the excavation, these specimens also display evidence for a more diverse array of worked raw materials.

Without the benefit of culturally diagnostic artifacts, any association of these materials with a more specific cultural group tied to the Protohistoric period is impossible to confidently

97 determine. While several nomadic tribes are known to have inhabited the region, the

Protohistoric period is generally associated with the migration of Athapaskan groups onto the

Central Plains. Several archaeological sites on the PCMS contain rock art motifs or consist of tipi ring residential locales with micaceous pottery (Hummer 1989; Loendorf et al. 1996; Sanders

1990), which appear to represent Apachean occupation of the region during this timeframe.

According to the ethnographic account of the Oñate expedition of AD 1601, the region was largely occupied by the people of the Apache Nation (Wedel 1986:138) with the Comanche reportedly starting to push the Apache out of the area by the early 18th century (Zier and Kalasz

1999:250-259). The dates of the cache can be correlated with this general timeframe, which corresponds to a strong Apachean presence in the region. However, there is too little pertinent data to confidently suggest this cultural affiliation. As previously indicated, there is a high likelihood of additional intact portions of the cache remaining buried at the site. If additional investigations can uncover culturally diagnostic materials, then a more definitive statement regarding cultural affiliation could be made.

Given the potential for further data acquisition, not only within the cache feature, but across the overall site, this resource is recommended to maintain the current National Register- eligible designation and the protection measures observed at the locale should be retained.

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