Zone VI: Into the Eagle Cave Unknown

Zone VI: Into the Eagle Cave Unknown

By Charles Koenig

Since we began excavating the main trench in Eagle Cave in 2014, we have always had some idea of what to expect thanks to the previous work by the 1963 University of Texas excavations.  In 1963, Mark Parsons and Richard Ross spent three days illustrating the north wall of the “Old Witte Trench.”

VV167-E-W-profile

Digitized and colorized field illustration of the 1963 Eagle Cave profile drawn by Mark Parsons and Richard Ross. The deep column in the center was added several months after the upper profile was annotated. Many more lenses, layers, and levels were noted on this profile than made it into the simplified, published version below. Original scan courtesy of the Texas Archeological Research Laboratory.

ross-1965-fig4

Version of the profile that appeared in Ross’s 1965 Eagle Cave report. Only the major stratigraphic zones are noted.

Even though they did not record nearly as many “zones” and “lenses” as we have documented strats (units of stratification), we can correlate some of the 1963 stratigraphic zones to 2015/2016 strats because they took the time to illustrate and describe the different layers. Broadly speaking, UT recorded 6 major stratigraphic zones (1-6), in addition to many other lenses and layers within zones. In Zones 1-5, UT recovered a variety of cultural debris (chipped-stone tools, plant and animal remains, and our favorite – burned rock), and the earliest deposits in Zone 5 were dated to 6500-7000 B.C. (Ross 1965). However, they stopped excavating at the top of Zone 6 because it was considered a “sterile layer of yellowish limestone spalls and dust.”

41VV0167_AMIS30243_029

One of the 1963 Eagle Cave crew members beginning to dig the deep test through “sterile” fill. The white sediment at the man’s feet is Zone 6. View is looking west. Image courtesy Texas Archeological Research Laboratory.

From the outset of our work in Eagle, we have been guardedly optimistic the deposits from Zone 6 and deeper might not be sterile, but simply UT did not excavate far enough to find the next layer of cultural material. In reading the site journal for the 1963 work, we realized the UT crew stopped excavating at Zone 6 not only because they interpreted it as being sterile, but also because they simply ran out of time to excavate any deeper. They did sink a deep test to bedrock at the end of their work, but this was quickly excavated, and from what we can gather, they did no detailed recording or screening of materials that came out of this test. So, as we began excavating into the top of Zone 6 at the end of our last session (the last week in March) we were excited because we knew from that point down we would be excavating into the unknown – the oldest (>9000 years), minimally explored deposits within Eagle.

STrench_UTZones

South trench in Eagle Cave profile as of 4/17/2016. Top image is just of the orthophoto of the trench, and the bottom is the same image superimposed with our interpretation of UT Zones 1-6 .

First Contact

The first place we excavated into Zone 6 was towards the rear wall in the site. Several of us (Kelton, Justin, and myself) were excavating units to expose a profile section, when Justin uncovered a most surprising artifact: a thick fragment of what appeared to be bison long bone.

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Justin working in Zone 6 (white/yellow in profile).

In addition to the bison bone fragment, Justin also recovered two chunky biface fragments. After the months of anticipation, wondering what we may or may not find, and then to find artifacts and bison bone in one of our first units … we were excited, to put it mildly! As most things go on an archaeological site the bison bone find occurred on almost the last day of the field session, so we had to wait two full weeks before we could investigate Zone 6 again.

41VV0167_Unit104_Artifacts

The two biface fragments (top) and sizable bison bone fragment (bottom) recovered in Zone 6 towards the rear wall.

The Trench Floor

Even though we all wanted to jump right in to excavating Zone 6 and seeing what was there, the first thing we did when we got back to work was to devote several days to removing disturbed fill from the bottom of the trench. After completing this dusty, hot, exhausting job we had exposed intact stratigraphy across the entire bottom of the trench. And, by removing the disturbed fill, we exposed more or less exactly the floor of the 1963 excavations into Zone 6.

Before&After_F14

The crew removing disturbed fill from the bottom of the trench (left), and the top of Zone 6 exposed in the bottom of the trench (right).

Once we had the top of Zone 6 exposed across the trench floor, we laid out several units with the goal of excavating down in the trench floor to give us room to work as well as expose profiles on the south wall. However, after only excavating about 10 centimeters below where the UT excavations stopped our excavations slowed dramatically when we started finding bison bone fragments; lots of them.

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The scatter of bison bones as originally photographed in Unit 109.

Unlike the single bone fragment Justin found in the upper Zone 6 towards the rear of the site, Emily, Spencer, and Bryan began exposing dozens of fractured bison bones scattered over a 5 meter area. We knew we had something really cool, and that Zone 6 was definitely not sterile!

41VV0167_Feature14_Top

The top surface of Feature 14 (fragmented bison bone scatter) as initially exposed in the Eagle Cave trench floor. The bison bones are slightly more yellow than the surrounding white/yellow rockshelter sediments.

Feature 14

As we continued to expose more and more bone, we realized these bone fragments were all related to one another and likely represent a single behavioral episode. Because of our working interpretation that the bones were fractured and strewn across the extant surface of the shelter in a single event, we gave the bone scatter the designation Feature 14 (the 14th formally designated feature recorded in Eagle Cave since 2014). The feature designation also means we wanted to take special care in how we went about recording the provenience of the bones. To do this we took a series of SfM models and shot in with the TDS many of the bones.

41VV0167_Feature14_108-114

Intermediate map showing Units 108 and 114 with additional bison bones exposed.

41VV0167_Feature14_109

Intermediate map showing Units 109 and 115 with additional bones exposed. The cluster of rock in the center of the image is Feature 15, a likely hot-rock thermal feature.

We were also very fortunate to have Art Tawater on hand that week as one of our volunteers. Art is a longtime member of the Texas Archeological Society and the Tarrant County Archeological Society, and one of his passions and areas of expertise is zooarchaeology. After the bones were mapped in (piece-plotted with TDS shots) and photographed, Art made a preliminary field ID for the various bones. This was a huge help because none of us (except Black) had any experience with excavating bison bones, let alone trying to figure out what element each bone fragment might be from!

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Art (left) helping Spencer (right) ID and package up bison bone for transport out of the site.

Mapping in the bones and collecting field observations slowed down the removal process, but we wanted to collect as much data in the field as we could so that when our collaborating zooarchaeologists Chris Jurgens and Haley Rush finally get to see the bones they will be well armed for the analysis to begin!  Plus, while the bones were well preserved, they had been purposefully fragmented originally  and some were crushed and cracked by the overlying deposits and did not remain intact upon careful removal.   Our detailed photographic record and Art’s field observations will allow a more complete analysis of the butchering and processing activities that took place on this surface over 9,000 years ago.

41VV01678_BisonMandible

One of the few diagnostic bones we recovered: a proximal left mandible (jaw) fragment from a juvenile bison with deep cut marks on the posterior side. This bone is visible in the Unit 109-115 image above.

Not Just Bone

In addition to the scattering of bison bone, we also found a modest amount of associated lithic debitage and stone tools. If you look closely several of the tools are visible in the above maps. It is telling that most of the chert artifacts appear to be made of only two or three cobbles judging from the matching colors and textures.  This bespeaks a short-term occupation during which only a few cobbles were knapped.

F14_Stonetools

Two bifacial tools found in direct association with the bison bone of Feature 14. Some of the debitage recovered appears to be the same raw material.

And although there is not the dense concentration of fiber within Feature 14 as in other areas of Eagle, we did recover some very badly decomposing organics.

41VV0167_TS6_U114_L2_FN34411_0674

A decomposing piece of wood recovered during excavation of Feature 14.

And I also can’t forget to mention the possible hot-rock thermal feature (Feature 15) found at the east edge of the bison scatter, with bones above and below rocks that appear burned!

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Chalkboard shot of Feature 15, a likely hot-rock thermal feature in direct association with the scattered bison bones.

So What Does it All Mean?

We just finished excavating the main portion of Feature 14 earlier this week, so it is really too early to even say the analysis has begun, but we can at least offer up some of our preliminary observations and working ideas. Based on the how fragmented the bones are, we hypothesize Feature 14 represents a bison butchering and processing locale/event within Eagle Cave; possibly that of a single juvenile bison (portions thereof).

41VV0167_Feature14_bonescatter

The outline of all mapped bison bones (in black) superimposed onto the initial Feature 14 exposure. The most complete bone–a rib–was recovered at the boundary between Units 114 and 109. All the other bones are fragmentary.

Not only were most of the bones fragmentary, but very few had diagnostic (articular) ends left. In most cases, the field ID was either “medial rib fragment” (~90% of bones) or “long bone shaft fragment” (~8%) of the bones. The fragmented nature of the bones suggests that the people may have been trying to extract bone marrow or render grease from the bones after the meat was removed.

We also have some interesting horizontal distributions of certain artifacts and bones. The areas where we found the highest number of bones with cut marks overlaps with where most of the debitage is clustered. Bones with cut marks plus many flakes indicates this location was where people were cutting bone and/or meat and needing to resharpen their tools. It was also telling to find the relatively few burned bone fragments we found appear to have been concentrated around several thermally altered rocks and scattered charcoal!

41VV0167_Feature14_interpretation

Distribution/highest concentrations of burned bone, bones with cut marks, and debitage overlaid against the bone scatter.

We were also fortunate to recover a projectile point from the same layer as the bison bone. Although not directly associated, this dart point fragment was recovered just to the west of the majority of the bison bones and is made of a very similar dark chert material as much of the debitage.

41VV0167_Feature14_DartPoint

From top left: photograph of dart point fragment in situ; both sides of the dart point in the lab; map showing the location where the dart point was recovered in relation to the bison bone.

At the moment we are not ready to officially type the point, but it is a lanceolate, contracting stem dart point fragment that shares several attributes of Angostura points.

Where to from Here?

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Myself, Jack Skiles, and Steve ponder Feature 14 when it was first exposed.

The fact that we encountered Feature 14 as quickly as we did after beginning into the “sterile” deposits of Eagle Cave gives us hope for additional, older, cultural deposits below. We do not know how old the bison bones are at the moment, but we will be sending out radiocarbon samples soon. We have had a lot of fun excavating this intriguing feature, and we look forward to sharing new findings as we make them!

41VV0167_Feature14_Profile

The location of the Feature 14 bone scatter (linear cluster of yellow dots) and the original bison long bone fragment discovered towards the rear wall. We are excited by the prospects of what we may find as we go deeper into unknown Eagle Cave!

Extending Arenosa Shelter’s Reach: Zooarchaeological Research in Eagle Nest Canyon 2015

By Christopher J. Jurgens and Haley E. Rush

**This post is the third of several that give additional details regarding some of the different analyses that are currently being conducted with material from Eagle Nest Canyon.**

Chris and Haley stand in front of their poster at TAS.

Chris and Haley stand in front of their poster at TAS.

Introduction

The Eagle Nest Canyon (ENC) faunal diversity has been significantly less than that found in Arenosa Shelter. Analysis of the faunal remains recovered in 2014 from Eagle Cave and Skiles Shelter has expanded the species diversity from that previously reported. Subsistence remains from the ENC sites show a reliance on deer and rabbits from the canyon and uplands, together with fish from the Rio Grande. Further alteration by bone technology processes similar to Arenosa Shelter is also present in the ENC faunal materials.

Skiles Shelter, site 41VV165 (left), and Eagle Cave, site 41VV167 (right).

Skiles Shelter, site 41VV165 (left), and Eagle Cave, site 41VV167 (right).

Methods and Materials

Analysis methods were similar to those used in the Arenosa Shelter study, with the addition of large mammal bone fragmentation. Differences in teeth, bone, antler, and shell were used to classify animals by taxa. Specimens were identified based on size and visual characteristics of skeletal elements or teeth. Visual characteristics were used to determine age classes.  Cultural modifications to bone were recorded as in the Arenosa Shelter study.  These included disarticulation, skinning, and removal of meat.  Similarly, the degree of burning methodology used in the Arenosa Shelter study was applied to the ENC study with further refinement.  The presence of earth oven deposits in the ENC rock shelters complicated determination of evidence for bone modification through cooking, but different causes for burning were recognized.

Results

Animals Present

To date, analysis of faunal remains has identified 394 fragments surface-collected from Eagle Cave in 2014 and over 300 of the approximately 2,050 fragments excavated from Skiles Shelter in 2014. Twenty three (23) taxonomic assignments have been made for specimens from Eagle Cave, including bison, deer, artiodactyls (deer and/or antelope, turtles (softshells and cooters), rabbit (jackrabbits and cottontails), catfish, bass or sunfish, canids (fox or coyote), rats, undifferentiated small, medium, and large mammals, and undifferentiated small and medium birds.  To date, twenty nine (29) taxonomic assignments have been made for specimens from Skiles Shelter.  More fish taxa are present, as are more small mammals.  Bison is not present in the specimens analyzed at this point.  Hawk remains have been identified.

Taxa Frequency Comparison by Site

Subsistence Remains

Many of the faunal remains present in Eagle Cave and Skiles Shelter have been altered through human subsistence activities.  Skinning, disarticulation, and removal of meat all left distinctive cutmarks on animal bone in the two sites.  Specific types of meat removal indicate filleting of meat from fish, rabbits, or deer, potentially for drying and storage.

Specimen #20031-8, Catostomid Sucker Vertebra with Filleting Damage, Skiles Shelter (41VV165), Excavation Area 1, Unit G, Layer 2

Specimen #20031-8, Catostomid Sucker Vertebra with
Filleting Damage, Skiles Shelter (41VV165),
Excavation Area 1, Unit G, Layer 2

Specimen #20018-59, Jackrabbit Ischium (Pelvis) with Butchering Damage from Dismemberment, Skiles Shelter (41VV165), Excavation Area 1, Unit D, Layer 4

Specimen #20018-59, Jackrabbit Ischium (Pelvis) with Butchering
Damage from Dismemberment, Skiles Shelter (41VV165),
Excavation Area 1, Unit D, Layer 4

Specimen #30020-116, Unprovenienced Deer Ischium Fragment with Butchering Damage from Dismemberment and Filleting. Surface-Collected from Eagle Cave (41VV167)

Specimen #30020-116, Unprovenienced Deer Ischium Fragment with Butchering Damage from Dismemberment and Filleting. Surface-Collected from Eagle Cave (41VV167)

Further fracturing of large mammal bones to remove marrow or to recover fat from the ends left bone fragments of varying sizes.  The intensity of marrow or fat recovery processing is evident from the size of the large mammal bone fragments. Roasting is evident on some specimens. Overall intensive burning (calcination) of some of the bone indicates heat exposure in excess of typical roasting. Much of the burned bone in the sites was discarded and incorporated into earth oven fill.

Bone Burning Pattern Comparison by Site

Large Mammal Bone Fragmentation by Size Class Class 1 = 9 cm

Large Mammal Bone Fragmentation by Size Class
Class 1 = Class 3 = 3-6 cm, Class 4 = 6-9 cm,
Class 5 = >9 cm

Bone Technology Debris

After needs for meat and hides were met, remaining animal bone was sometimes further altered into tools or ornaments.  Using stone tools or flakes, bone was scored, grooved, and snapped to rough shape, then scraped and ground to a final shape.  Remnants of these steps are evident on 35 bone or antler tool fragments or bone manufacturing debris found at the sites during the 2014 field season.

Surface-Collected from Eagle Cave (41VVSpecimen #30025-122, Unprovenienced Spatulate Tool Fragment 167)

Surface-Collected from Eagle Cave (41VVSpecimen #30025-122, Unprovenienced Spatulate Tool Fragment 167)

Acknowledgements

We wish to thank the Skiles family for its long and careful stewardship of the  archeological resources in Eagle Nest Canyon.  We also thank Dr. Steve Black of Texas State University for the opportunity to study zooarchaeological aspects of the sites in Eagle Nest Canyon as part of the Ancient Southwest Texans Project.

 

**A full PDF version of the poster is available here: Jurgens&Rush_TAS2015_Faunal_FINAL

 

References

Gilmore, Zachary

2007  Large Mammal Utilization and Subsistence Stress in Late Prehistoric South Texas. M.A. Thesis, Department of Anthropology, Southern Illinois University. Carbondale, Illinois.

Jurgens, Christopher J.

2005  Zooarcheology and Bone Technology from Arenosa Shelter (41VV99), Lower Pecos Region, Texas.   Unpublished Ph.D. Dissertation, Department of Anthropology, the University of Texas at Austin.  Austin, Texas.

Outram, Alan K.

1998  The Identification and Paleoeconomic Context of Prehistoric Bone Marrow and Grease Exploitation. Unpublished Ph.D. Dissertation, Department of Archaeology, University of Durham.  Durham, U.K.

2001 A New Approach to Identifying Bone Marrow and Grease Exploitation: Why the “Indeterminate” Fragments should not be IgnoredJournal of Archaeological Science. 44(28):401-410.

Rush, Haley E.

2013  The Rowe Valley Site (41WM437): A Study of Toyah Period Subsistence Strategies in Central Texas.  Unpublished M.A. Thesis, Department of Anthropology, Texas State University.  San Marcos, Texas.

 

From the Bowels of the Lower Pecos

By Emily McCuistion

Howdy, you may have seen mention of me on this blog and on our facebook page but this is my first official post for the ASWT project. I introduced myself at the beginning of the season, but to refresh I am one of the three interns on the Eagle Nest Canyon 2015 Expedition. My previous archaeology work has been primarily with the National Park Service and Forest Service, neither of which generally have the resources to undertake studies such as this one. This is the first in-depth archaeological excavation I have worked on and I’ve been blown away by the site itself, the other expedition members and the leadership overseeing the project, and our numerous collaborators who contribute their specialized expertise on various and sundry sub-disciplines (chemistry, botany, entomology, geology…the list goes on). It seems that there are infinite directions that project-related studies could go. I love interdisciplinary research and so I’ve been especially taken with the subject on which I am blogging. These delicate resources contain a world of information inside them- I’m glad to introduce the coprolites of Eagle Cave!

Me, poofing sediments off a coprolite.

Me, poofing sediments off a coprolite. I’m wearing a dust mask to protect my airway from the fine particles we stir up.

The study of human coprolites, also known as paleofeces, palaeofaeces, or simply dried-up old poop, was not regarded as important by the archaeological community until the mid-20th century.  Now we realize that we have a lot to learn from coprolites; they can inform us on past diets and ecosystems, the health of an individual, and the manner in which one ate and pooped. Archaeologists can look at the plant and animal macrofossils (visible undigested remains), tiny pollen grains, phytoliths (micro-structures created by plants), viruses, parasites, and even bugs found in coprolites!  Further, coprolites can be directly radiocarbon dated (so we can determine how old they are) and they preserve not only the DNA of the person who made the deposit, but also the DNA of the animals and plants that were consumed. Though perhaps less revealing, shape, color and of course location of the deposit are relevant. The study of odor, though noted by many researchers, has as yet not proved of scientific value.

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FN31041 from Eagle Cave. We give each coprolite a unique specimen ID or Field Number (FN). We’ve found that one specimen can be made up of several segments representing one bowel movement.

Victoria excavating a coprolite. After documentation and careful extraction we transport the coprolites to the lab in boxes so that they are not inadvertently crushed.

Victoria excavating a coprolite. After documentation and careful extraction we transport the coprolites to the lab in boxes or by hand so that they are not inadvertently crushed in our packs.

Though I hesitate to mention paleontology- the oft confused (with archaeology) but unrelated study of dinosaurs- the study of dinosaur coprolites pre-dates the study of human. We are indebted to paleontologists for first recognizing the potential in coprolite study. The word coprolite, derived from Greek, was termed in the 1830s by an English paleontologist and translates to “dung stone.” I have yet to hear about human coprolites that have turned to stone, nonetheless the use of the word coprolite to describe human feces in an archaeological context is pervasive.

The Lower Pecos Canyonlands is famous for its coprolite studies, specifically those conducted on specimens excavated from Hinds Cave. Coprolites have been identified at other sites in the region but none have been so well studied as those from Hinds.

HC76-B-latrine

Profile of latrine deposit in Hinds Cave. Coprolites are in the upper right corner. Photo from texasbeyondhistory.net.

Hinds-HJS-76-dust

Hinds Cave is north of Eagle Cave, along the Pecos River. This photo from texasbeyondhistory.net was taken during the 1970s excavation, as evidenced by the excavation dust swirling from the rockshelter.

Even knowing that coprolites preserve well in the Lower Pecos we didn’t really expect to find them in Eagle Cave – coprolites were not found during the 2014 field season in any of the shelters investigated in Eagle Nest Canyon. Happily, during our excavations this spring we were excited to find an abundance of well preserved coprolites!  Thus far over 80 coprolite specimens have been inventoried during this field season, the vast majority of them excavated from near the front of the rockshelter and approximately a meter or two below the surface.

South Trench Profile of Eagle Cave with point-provenienced coprolites.

South Trench Profile of Eagle Cave with coprolites plotted- click on the image to enlarge.

At Eagle Cave the coprolites are mainly found in areas of discarded fire-cracked rock and plant remains (See: Between a Rock and a Heart Place for info on the fire cracked rock in Eagle). Sometimes they are found within compacted and dry-cracked sediment which we hypothesize may be evidence of urine-soaking, and of which we are taking samples. Sometimes a coprolite is found near a smooth river cobble; speculations about wiping methods ensue…

Matt "Call me John" Larsen was the first to start finding coprolites in the FCR/fiber layers near the front of the shelter.

Matt “Call me John” Larsen, pictured here saying “poop” in American Sign Language, was the first to start finding coprolites in the fiber layers near the front of the shelter.

Analysis of the coprolites is not yet underway but there are some basic observations that can be made about the Eagle Cave specimens. (We are assuming all the specimens we have collected are human; however, it should be noted that other animals have pooped in Eagle Cave over the preceding 9000 years and some of the specimens we have collected may not be human.)

Shape- It has been found that plump, shapely coprolites are often from a fiber/plant-heavy meal while the “loose” ones may be from an individual who had recently consumed a lot of meat. There are, however, many other reasons that one could have had fluid bowel movements: parasites, water containing algae-born toxins, plants with a laxative effect (sotol and lechuguilla – both baked in earth ovens – are known to have this effect on some people), even emotional states- fear has been cited- can cause diarrhea.

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The “most-shapely” and largest of our specimens, and a good example of a segmented bowel movement: FN30984.

FN31296 fell a little flat.

FN31296 fell a little flat.

Size is affected by several conditions, including length of time since the last bowel movement and types of food eaten. Meals based on a single type of food can result in smaller stools, though a vegetarian diet can result in a larger stool than an omnivorous diet.

Diminutive FN31109

Diminutive FN31109. Compare it to FN30984 pictured above.

Color can be indicative of diet; the darker specimens often result from meat consumption while the lighter ones can be indicative of a vegetarian and/or carbohydrate-rich meal. When dried, however, colors change. Nonetheless, it is interesting to note color variations.

FN31048 is unusually orange in color.

FN31048 is unusually orange in color.

FN31103 is taupe.

FN31103 appears greyish, though it is important to note that our specimens still have sediment from excavation clinging to them.

FN31063 has a warm brown color, and lots of fibers.

FN31063 has a warm brown color, and lots of fibers.

Macrobotanicals, bones and fur (Macrofossils): Botanists and faunal experts can identify large plant and animal remains within coprolites. Thorough analysis requires breaking down the coprolite and separating it into constituent parts, however, macrofossils are sometimes visible on the surface. Many thanks to our faunal and botanical associates- Christopher Jurgens, Haley Rush, Kevin Hanselka, Leslie Bush, and Phil Dering- for helping to tentatively identify bones and seeds in a couple specimens (meet our zooarcheology and archeobotany heros here: “Come Visit:” A Zoooarchaeologist Is Lured Back to the Lower Pecos and here:The Archaeobotanical Team Forms).

This bone in FN30983 came from a jackrabbit-sized animal. In the words of Charles, "Ouch."

This bone in FN30983 came from a jackrabbit-sized animal. In the words of Charles, “Ouch.”

The diamond-shaped macrofossil in the center of this stool has been identified as a mesquite endocarp.

The diamond-shaped macrofossil in the center of this stool has been identified as a mesquite endocarp. The peak sticking off the backside are fibers from a plant such as lechuguilla or sotol.

FN30984 is chock full of seeds!

FN30984 is full of seeds!

FN30983 contains what looks like prickly pear seeds, the tastiest desert food I've ever eaten (unless you count Jack Johnson's mesquite snickerdoodles).

FN30983 contains what looks like prickly pear seeds, the tastiest desert food I’ve ever eaten (unless you count mesquite snickerdoodles).

Insects: We have yet to see insects in the Eagle Cave coprolites (though a fly pupal case rolled out of a bagged specimen when I removed it for this photo shoot) but we sometimes see their bore-holes. In her 1978 dissertation on Hinds Cave coprolites, Glenna Williams-Dean reported that the experimental stools (a comparative collection of modern specimens left to dry in a rockshelter near Hinds Cave) were up to 95% consumed by insects! When conditions are not suited to an insect, especially a flying insect, it quickly moves on. For this reason they are good indicators of change in climactic and other conditions. (see: Archaeoentomology? for more details)

Holey crap- I believe insects created this swiss cheese affect in FN31021.

Holey crap- I believe insects created this swiss cheese effect in FN31021.

One morning I resumed excavation of a coprolite I hadn't finished exposing the previous day. When dusting off the specimen this beetle crawled out from under it! Perhaps coprophagous (dung-eating) insects are interested in vintage as well as fresh specimens.

One morning I resumed excavation of a coprolite I hadn’t finished exposing the previous day. When dusting off the specimen this beetle crawled out from under it! Perhaps coprophagous (dung-eating) insects are interested in vintage as well as fresh specimens.

As mentioned previously, there are numerous other avenues for coprolite study (e.g., pollen, DNA/genetics, phytoliths, lipids, parasitism, general health, dietary nutrition, seasonality, medicine, food processing techniques, past environment, food trade/exchange, and food storage), but until we begin the analysis of the Eagle Cave specimens I cannot go into great detail.  However, I can provide a brief synopsis (definitely not exhaustive) of some things archaeologists have learned from conducting coprolite studies in the Lower Pecos.

Let us start at the beginning of the digestive system: the mouth. A significant malady affecting ancient Lower Pecos people was dental wear and eventual complete toothlessness by their 40s. Danielson and Reinhard (1998) studied coprolites to examine possible causes for the dental wear and tooth loss in Archaic-age Lower Pecos skeletons. They considered several hypotheses, including that the grit from food-processing stones was wearing down the tooth enamel.  Interestingly, they found no such grit in the coprolites they studied. Rather, calcium oxalate phytoliths (microscopic structures found in certain plants which pass unscathed through the digestive system) are found in abundance in Lower Pecos coprolites. They occur in the agave and cactus plant families (Agavaceae and Cactaceae respectively), and were found to be harder than tooth enamel. Not coincidentally, agave and cactus are a major part of the aboriginal diet of the Lower Pecos people. Other factors probably contributed to dental wear and loss, but a major cause was identified.

The phytoolith pictured up top is prickly pear. The lower is a sotol phytolith (texasbeyondhistory.net).

The phytolith pictured up top is prickly pear. The lower is a sotol phytolith (texasbeyondhistory.net).

So, we have a population of largely toothless people who still must eat. But, must they chew? Specimen FN30984 from Eagle Cave, and some found at other sites, indicate there was not always much chewing – what Dr. Black charmingly calls the “grab it and gulp” method of eating.

That brings us to what they were ingesting. Certainly food availability varies with the seasons and the millennia, but there is coprolite evidence people were eating many of the same foods that are available today (e.g., sotol, lechuguilla, cattail, wild onion, prickly pear, insects, fish, deer, pronghorn, rodents, reptiles, bison [the kitchen ran out of that a few years ago], and too many other foods and medicinal plants to go into at this time – check out the TBH exhibit on the Ethnobotany of the Lower Pecos Canyonlands for more information about Lower Pecos diet.  So far we have only been able to identify a few different seeds in the Eagle Cave coprolites but as we begin detailed analysis of the coprolites we will learn a great deal more.

Finally, when the meal is ready to be passed a decision has to be made on where to release the body’s effluent. I don’t know if there are enough sites in the region with mapped coprolite “deposits” to make assertions about latrine location preferences, but it was found that the latrine at Hinds Cave was at the back of the shelter. The vast majority of coprolites from Eagle Cave have been collected from near the front of the shelter at the top of the burned-rock-strewn talus slope.

Dr. Black takes a close look at the Eagle Cave coprolite collection.

Dr. Black takes a close look at the Eagle Cave coprolite collection.

For more discussion about coprolites from the Lower Pecos and Hinds Cave, check out the TBH exhibit on Hinds Cave to learn more.  So much more on coprolites could (and will) be written, but right now other doodies call!

References Cited:

Danielson, Dennis R. and Karl J. Reinhard                                                                                          1998 Human dental microwear caused by calcium oxalate phytoliths in prehistoric diet of the lower Pecos region, Texas. American Journal of Physical Anthropology 107: 297-304.

Williams-Dean, Glenna                                                                                                                         1978 Ethnobotany and cultural ecology of prehistoric man of southwest Texas. Ph.D. Dissertation, Department of Anthropology, Texas A&M University, College Station.

“Come Visit:” A Zoooarchaeologist Is Lured Back to the Lower Pecos

by Chris Jurgens and Steve Black

I (Chris) recently joined the Eagle Nest Canyon research team after Steve kept urging me to “come visit.”  He lured be back to the Lower Pecos because of my research specialty – I study animal bones.  Also known as faunal materials, animal bones are common in the dry rockshelters.  Zooarchaeologists like me study both the faunal materials and artifacts made from bone.

Dr. Chris Jergens studying faunal remains under a microscope.

Dr. Chris Jurgens studying faunal remains under a microscope.

What is Zooarchaeology?

E. J. Reitz and E. S. Wing (1999) define zooarchaeology as the study of animal remains originating from archaeological sites.  Zooarchaeology studies those remains from a specifically anthropological perspective, instead of a biological or paleontological perspective.  Some archaeologists, Reitz and Wing included, further separate the study of vertebrate bony faunal remains as osteoarchaeology.  We would also include other vertebrate faunal remains, such as antlers, teeth, skin, fur, and other soft tissues.

Zooarchaeology developed over the past 80 years to investigate the physical constituents of animal bodies, their resulting byproducts, and the remains of any parasites that might have originally been present. Zooarchaeological faunal studies are also used to investigate site formation, biological processes, and cultural processes that are reflected in the particular collection (or sites) being studied.  The anthropological perspective addresses the complex interaction between humans, their environment, and the consequences of that relationship.

Context of faunal remains is the key to understand their role in any site.  Are the faunal remains found in an archaeological deposit there strictly as a result of natural processes? Are the faunal remains spatially associated with other cultural materials?  If the faunal remains are spatially associated with cultural materials, then the zooarchaeologist must ask other questions.  Have the faunal remains been modified by processes produced by cultural behaviors (skinning, butchering, tool manufacture or use, bone breakage for marrow removal or bone grease production, etc.)?

These are the animal bones recovered from one layer of one excavation unit in Skiles Shelter.  Much of the bone is from small mammals (e.g., rabbits, squirrels) but the large fragment on the right is probably from deer.

These are the animal bones recovered from one layer of one excavation unit in Skiles Shelter. Much of the bone is from small mammals (e.g., rabbits, squirrels) but the large fragment on the right is probably from a deer.

Zooarchaeological studies are important aspects of any archaeological project for several reasons, a prime one being to understand past environments.  Animals, particularly small ones like rodents and rabbits, often thrive only in certain ecological conditions, like arid uplands or well-watered canyons. By studying a faunal assemblage, a group of bones from same archaeological context like a rich midden layer dating to the Late Archaic about 3,000 years ago, we can make inferences about the paleo-environmental conditions in the vicinity.

Faunal materials can also open windows into how prehistoric cultures functioned.  Archaeologists use bones, teeth, and other faunal materials to address questions about subsistence (diet and hunter-gatherer economy) and in the Lower Pecos, later groups often relied heavily on small mammals and fish.  And we try to figure out the exact techniques used in making bone tools and ornaments and how these crafted bone items were used.  Certain items, like bone rasps used to make rhythmic sounds associated with ritual, may reflect belief systems.

Unfortunately, even though the dry rockshelters of the Lower Pecos often yield extremely well preserved animal bones, faunal assemblages have rarely been carefully studied, especially in comparison to the many studies of chipped stone artifacts that have been done.  Prior to my work, the only other major faunal study in the region was Kenneth Lord’s 1983 dissertation study of animal bones from Hinds Cave.  For my own doctoral dissertation I studied a sample from the nearly 50,000 faunal specimens excavated from Arenosa Shelter (41VV99).  This deeply stratified site is on the Pecos River near its confluence with the Rio Grande, about 14 miles southeast of Eagle Nest Canyon and Langtry (see www.texasbeyondhistory.net/arenosa/ to learn more about Arenosa).

Bone preservation at Arenosa Shelter was excellent, especially in Late Archaic and Late Prehistoric strata.  Animals represented in the sample included terrestrial and aquatic species from a variety of fish, turtles, rodents, rabbits, carnivores, and deer to extinct animals, such as Pleistocene horse, deer, and bison.  The Arenosa fauna provided an excellent basis for both paleo-environmental reconstruction and the first detailed study of bone technology in the Lower Pecos. I also published a 2008 article “The Fish Fauna from Arenosa Shelter (41VV99), Lower Pecos Region, Texas.”

Dr. Jergens identified this catfish vertebrae from Eagle Cave.  Based on the size of the bone, this fish would have weighed over 50 pounds!

Jurgens identified this catfish vertebrae from Eagle Cave. Based on the size of the bone, this fish would have weighed over 50 pounds!

On to a Fuller Understanding

The faunal collections from Eagle Cave, Skiles Shelter, and Kelley Cave can be compared with that from Arenosa Shelter and expand our understanding of life-ways in the western part of the Lower Pecos region.

Sixty percent of the Arenosa Shelter faunal materials and bone artifacts were found in upper deposits (strata 4 – 9), a Terminal Late Archaic context dating between about 2,300 and 1,300 years ago.  Many of the deeper and earlier Middle and Early Archaic deposits at Arenosa Shelter (strata 12 – 36) were heavily damaged by high energy Pecos River flooding.  The floods removed most of the bone these deposits may have originally contained, especially that from smaller animals.  Remaining bone in these strata is quite often in secondary context.

Although we are still evaluating the contexts of the ENC sites, most of the faunal material we have recovered is well preserved, especially the bones found in organic-rich layers like those seen in the upper part of Kelley and Eagle Caves.

Chris Jergens analyzes a bone tool recovered from Skiles Shelter.

Chris Jurgens analyzes a bone tool recovered from Skiles Shelter.

Comparison between Arenosa Shelter and the Eagle Nest Canyon (ENC) sites will primarily focus on Late Archaic and Late Prehistoric bone technology and subsistence economies.  The ENC sites appear to contain very similar faunal remains, including those of small to large mammals, fish, birds, turtles, and other reptiles. Much of the faunal material and bone artifacts from the Eagle Nest Canyon sites have not been burned.  They will be directly comparable to the Arenosa Shelter observations, including eco-niches targeted by the inhabitants, specific subsistence behaviors that include filleting of fish and specialized skinning of mammalian carnivores, and use wear on tools or ornaments.  Who knows, maybe we’ll even find catfish spine tools as at Arenosa Shelter or other, new and unexpected evidence for how the prehistoric inhabitants of Eagle Nest Canyon lived in this austerely beautiful land.

 

 

References

 

Jurgens, Christopher J.

2005  Zooarcheology and Bone Technology from Arenosa Shelter (41VV99), Lower Pecos Region, Texas. Unpublished Ph.D. dissertation, Department of Anthropology, The University of Texas, Austin.
2008  The Fish Fauna from Arenosa Shelter (41VV99), Lower Pecos Region, Texas. Quaternary International185:26-33.

 

Lord, Kenneth J. 

1984   The Zooarchaeology of Hinds Cave (41 VV 456).  Published by the Department of Anthropology at Texas A&M in an unnamed Hinds Cave report series. [Published version of  Lord’s 1983 University of Texas at Austin Ph.D. dissertation.]

 

E. J. Reitz and E. S. Wing

1999    Zooarchaeology. Cambridge Manuals in Archaeology.  Cambridge University Press.