Month 1 in Review

By Brooke Bonorden

As the end of January (and our fourth week of excavations) rapidly approaches, it seems appropriate to give an update of our overall progress with the Ancient Southwest Texas Project.

When Dan Rodriguez began excavations in Skiles last June, he encountered a thick flood deposit in both of his 1 x 1 meter units.  This was very exciting because it suggested that any archaeology beneath the thick Rio Grande flood-mud could be intact and undisturbed.  So, four weeks ago we began to expand on Rodriguez’s two units to address two main research questions: 1) what is the depositional history (both natural and cultural) within Skiles Shelter and 2) how much earth oven plant processing is represented by the substantial burned rock midden talus at the site.

In order to get an idea of the depositional history of the site, we have opened five new units (bringing the total to seven units in Skiles), and have excavated multiple layers within each unit. For those unfamiliar with archaeology this may not sound terribly impressive considering we have spent almost an entire month in the field, but when taking into account all of the paperwork/photography/lab work accompanying each unit and layer we have made significant progress.  We have also produced 3D models of each unit/layer that has been excavated, deriving these images from a series of overlapping photos. These models are far more detailed than any scaled drawing of a unit or profile could ever be, so our techniques are essentially revolutionizing traditional archaeological methods. We are also transitioning from recording our progress on paper field forms to using both tablets and laptops for digital recording.

How many archaeologists does it take to supervise one crew member?

How many archaeologists does it take to supervise one crew member?

No formal analysis of the artifacts collected from these units has been conducted, so my observations of what we have learned from the site thus far are not necessarily profound, but I can tell you a couple interesting things.  The large flood deposit appears to overlay an earth oven facility (aka, burned rock midden or BRM) where indigenous peoples used earth ovens to process plants like lechuguilla and sotol.  Where we have exposed the flood deposit and the BRM layer, it appears the BRM was higher in elevation toward the drip line of the shelter, which caused the flood to deposit sediment in a thicker layer toward the back wall of the shelter.  As of this moment we have collected several diagnostic projectile points, but have only exposed the top of the BRM and have not received any radiocarbon dates, so we do not know much more about the site.

Variety of dart and arrow points recovered from Skiles Shelter.

Variety of dart and arrow points recovered from Skiles Shelter.

Skiles excavations as of 1-27-2014

Skiles excavations as of 1-27-2014

We have recently begun switching gears so to speak, and are beginning preparations for our Eagle Cave excavation. We have spent the last couple days stabilizing trails into the site to help protect it.  Tomorrow we will begin laying down rubber matting on trails inside the shelter to help keep down the dust and prevent potential damage by visitor traffic.  Last week when we did the Pole Aerial Photography of Eagle Cave and established our datums from which we will calculate our elevations, northings, and eastings (necessary for site mapping).  We are also addressing logistical issues that we anticipate arising once we break ground at the site, but I won’t go into detail about that.

Crew building trails in Eagle Cave.

Crew building trails in Eagle Cave.

In addition to field work at Eagle Cave we have been preparing in another way by spending some of our free time reading over the previous excavation reports on the site. The first is on excavations carried out in the 1930s by the Witte Museum, and the second discusses excavations conducted by the University of Texas in the 1960s as part of a salvage project related to the creation of the Amistad Reservoir. I have particularly enjoyed looking at the photos from these excavations. The scenery stays the same through time, but so much about the people (and excavation methods) has changed!

All of that being said, we are four weeks in, our enthusiasm is still high, and nobody has lost an arm or a leg yet. So I would call our first month in the Lower Pecos a success!

Advertisements

A STEP BACK IN TIME – LIVING AT SHUMLA CAMPUS

By Bryan Heisinger

As the sun rises over the rolling hills east of the Shumla Campus, the thing that strikes me is how completely quiet and isolated the camp becomes when the day to day commotion of camp life is absent. Sitting on the patio rocking chair, I can stare out towards the horizon and see for miles in any direction across the rocky landscape that surrounds the Pecos River. It is hard to find any trace of civilization — this is Nature. The chirping of birds playing in the mesquite brush, the call of an occasional train passing south of the campus, and a random gust of wind whistling in the low lying shrubs are about the only sounds you will hear throughout the day. Now and again, I feel as if I stepped back to a time when Texas was young and wild. If a horse and buggy came rolling down the gravel driveway, I would be convinced.

Just a short walk up the knoll that sits behind the campus buildings, I can look south into Mexico and see the dark blue silhouette of the north east edge of the Sierra Madre Oriental mountain range looming far away in the distance.  In between the campus and the distant mountains lay close to 40 miles of dry, desolate, desert country.  From atop the knoll, I can also make out the south canyon wall of the mighty Rio Grande. Although, I can’t see the river from this viewpoint, I know the Rio is pushing her way south east through a series of bends and turns until she finally empties into the Gulf of Mexico.

When evening begins to set in and the sun begins to sink low, the sky above the campus slowly becomes a moving painting. Fantastic shades of blue, orange, red, yellow, and pink capture the upper atmosphere and mix together in a heavenly display of hue. Every night, I sit outside and watch this scene slowly fade to grey. After color has drained the sky, the constellations of Orion and Taurus begin to fill the night before me. Nighttime at camp can be eerily silent and very dark. It seems as if the strange creaks and noises from the buildings let loose when the sun goes down, just to keep me on my feet.  Nevertheless, I manage to sleep in the bunkhouse quite well.

The surrounding landscape is primitive, but the campus is more than accommodating to the crew’s contemporary needs.  With a stocked kitchen, wireless internet, and full library it is very easy to live far away from the city and be completely content.  This place will live fondly in my memories for the rest of my life.

Shumla Campus

Shumla Campus by Isaac Martinez

The Structure from Motion Revolution: Digitally Documenting the Archaeology of Eagle Nest Canyon

By Charles Koenig

In several previous posts we have mentioned the use of Structure from Motion (SfM) photogrammetry during the ENC project.  Before I begin explaining what SfM is, I want to explain how we (ASWT) came to be using SfM on the ENC project.  I was first introduced to SfM at the 2009 TAS Annual Meeting in Del Rio.  I had just received my BA from the University of Colorado in May 2009, and had only 5 months of field experience as an intern working with SHUMLA—in other words, I was young and impressionable.  I attended a presentation by Mark Willis where he explained how he used Microsoft Photosynth to create a 3D model from photographs he took using a hand held camera (for more info see Mark’s Blog: http://palentier.blogspot.com/).  To me, Mark was describing something straight out of video games and movies, and I remember thinking how cool it was that archaeologists were creating 3D images using just a camera!

Dr. Black’s (Steve’s) 2010 Texas State Archaeological Field School was the first time I was able to see Mark in action.  That summer I was finishing my internship at SHUMLA and gearing up to enter graduate school under Black at Texas State.  The field school was headquartered at the Shumla Campus on Jack and Missy Harrington’s Shumla Ranch and I was taking the field school unofficially as a SHUMLA representative.  Back to Mark in action.  He suspended a simple point-and-shoot camera about 100 feet up in the air from a kite and mapped the upland stone alignment site of Javelina Heights, which the field school was excavating.  The basic principle by which a 3D surface is created using SfM is to take dozens—or sometimes 1000’s—of overlapping photographs of the object/area being mapped.  These photographs are then put into specialized software that matches each photograph up to other photographs of the same area, and it builds a 3D surface from the 2D photographs.  This 3D surface, which is essentially a topographic map, can then have geo-referenced real-world coordinates (e.g., meters or UTM coordinates) assigned to the model so measurements can be taken from the surface.  Mark spent only a few hours on site, but he was able to produce a higher-resolution site map than the one we produced after 5 weeks and 1000’s of topographic shots with a Total Data Station.

A small sample of imagery captured from Javelina Heights (left); Mark Willis and Steve Black discussing rigging a camera to the kite (top right); Mark Willis flying a kite in the Lower Pecos (bottom right)

After Mark’s mapping of Javelina Heights on I was convinced—Steve slightly less so—that SfM was the way to go.  Again in 2011 Mark came out to Dr. Black’s field school and used a kite to map Little Sotol (a terrace/rockshelter burned rock midden along a tributary to the Devils River where the field school was held).  That year my fellow Coloradoan and graduate student Ashleigh Knapp and I were the field school teaching assistants and developing our Master’s thesis research projects (Little Sotol for her, the survey of Dead Man’s Creek drainage for me).  I began to experiment taking my own SfM shots of different rockshelters I recorded as part of my survey, and even with just my basic understanding of the technique I was able to produce 3D point clouds of rockshelters.  My early efforts were mere baby steps compared to what Mark was doing at Panther Cave as part of SHUMLA’s 2011 Field School (http://www.youtube.com/watch?v=vbmgpKKLMyY).  But, Mark’s work at Panther Cave coupled with my own experimentation was enough to convince Steve that SfM could be used effectively to map sites.  So, in 2012, during continued research along Dead Man’s Creek we began to use only SfM to map and document our excavations at three burned rock midden sites.

SfM models of Hibiscus Shelter (left) and Tractor Terrace (right). The model for Hibiscus was created using 950 photographs, and the Tractor Terrace model produced using 750. The photographs for both models were taken after excavations were completed.

After our work in the summer of 2012 along the Devils River, my TxState coursework was completed and I returned to SHUMLA to work part time as I completed my thesis; but, SfM was not forgotten.  At SHUMLA we began to produce 3D models of all the sites where SHUMLA was recording pictographs.  In part because we were constantly face to face with 3D models of archaeological sites, we began to realize what we were creating: a digital, interactive record of Lower Pecos archaeology. We were creating something that could be shared with the world.

As for me, I finished my MA in December, 2012 and worked full-time at SHUMLA through August.  I was one of the rock art instructors during the TxState Archaeological Field School at Eagle Nest Canyon that Steve co-directed with Carolyn Boyd.  I am now back at TxState working for ASWT as the project archaeologist and Steve’s second-in-command.

Fast forward to 2014 and the Eagle Nest Canyon project. We are using SfM to document and model sites, excavation units, excavation layers, profiles—essentially we are using SfM to photo-document anything and everything.  Depending on the size of the area being mapped, we can produce 3D surfaces with sub-millimeter accuracy.  In fact, SfM produces results rivaling LiDAR, but for a fraction of the cost.

With the help of Mark Willis, we have taken photographs from a UAV and remote controlled helicopter to create maps of the Eagle Nest Canyon area with centimeter resolution.

UAV imagery from Eagle Nest Canyon, courtesy Mark Willis.

Using cameras suspended from a pole (PAP, pole aerial photography), we have mapped the talus of Skiles Shelter and the floor of Eagle Cave to sub-centimeter resolution.

Image

Charles using PAP to map the surface of Eagle Cave (top left); Jacob and Charles running PAP in Skiles Shelter (top right); a 3D surface of Eagle Cave generated from 1800 photographs.

Using just a hand-held camera we have modeled all of our excavation layers and profiles so we can better understand the deposits of the sites we are excavating.

The crew works together to photograph a 1.5m deep profile in Skiles (top). The 3D model (bottom) was created from 85 photographs.

Archaeological excavation and testing is inherently destructive—we are excavating intact deposits that once we are finished will never be intact again.  Using SfM, we are able to create a 3D record of not only the archaeological sites, but also the archaeological process.  By creating 3D records of each layer, level, and excavation unit we can digitally preserve things that are destroyed through the course of excavation.

This is a goal shared by SHUMLA and Texas State’s ASWT Project, and we are both striving to create a 3D digital record of Lower Pecos Archaeology.  From burned rock middens to rockshelters and from pictographs to painted pebbles, we are collaborating to document as many sites and artifacts as we can using SfM.  Imagine a video game-like environment where you navigate into an unexcavated rockshelter, and walk over to an area where we are currently conducting excavations.  With one click of a button you can begin excavating the site just like we did – one layer at a time.  Inside every layer you can appreciate the artifacts, look at the rodent burrows, and ponder the microstratigraphy.  Once you finish looking at the dirt, you can turn your attention to the pictographs along the rear wall and begin exploring the data recorded by SHUMLA.

We have an obligation as scientists and stewards to both study the archaeology and preserve it for future generations—SfM provides us with a means to begin creating a digital archaeological record to be accessed and studied for generations to come.

Geoarchs in Action: Dirt by Many Other Names

By Steve Black and Jake Sullivan

Yesterday’s blog mentioned that geoarchaeologists Charles Frederick and Ken Lawrence would be with us in the field today.  For an archaeologist it is often a humbling experience to have a geoarch look at the same dirt you have been digging through and staring at for days—the things they see that we don’t!  They have both archaeological and geological training and whereas we ‘pure’ archaeologists look for cultural layers and cultural things, they look first at the natural formation processes.  How and when did the layers form, and how were they transformed since being created by the hand of man and the myriad vectors of ‘bioturbation’?  This may seem easy enough to decipher with a simple layer-cake stratigraphic profile, but what we have in the rockshelters of Eagle Nest Canyon is anything but simple—convoluted layers chopped up and partially blended by burrowing animals, insects, and the pits, fires, and scratching around that peoples ancient and historic have done.  Let’s introduce our collaborators of the geoarchaeological persuasion.

Dr. Charles Frederick is regarded by most as the preeminent geoarchaeologist working in Texas today and arguably one of the best in the world.  He earned his Ph.D. at UT-Austin under the famed geographer Karl Butzer and he has worked all across Texas and many other places in the world.  Charles taught in the University of Sheffield in the UK, but returned to Texas where he is an independent consultant who works as a subcontractor for many different firms and organizations.  What sets him apart is his encyclopedic knowledge of geology, pedology (study of soils), and natural science in general.  That and the way he approaches any research project—with an open, critical mind and the belief that something useful can be learned if you pose the right questions and link the big picture to the nitty gritty details.  Charles is a true scientist, he forms hypotheses (trial explanations) and then he tries to test them by seeking the hard evidence that could either disprove or strengthen the notion. 

His comrade in arms on this trip is Ken Lawrence.  Ken earned his M.A. at Texas State University where he studied under geoarchaeologist Dr. Britt Bousman.  He works for SWCA an Austin environmental consulting firm.  But like Charles he is here volunteering his time to help us because he likes the challenge of working in an area where few geoarchs have ventured. The chance to do pure research unfettered by regulation and the bottom line.  Ken, too, appreciates the opportunity to be able to spend time in the field with Frederick.  Geoarchaeologists often find it a bit frustrating to work with the unwashed (archaeologists who lack geological training) because we speak different lingo and we don’t look at the dirt through the same lens.  Watching the two of them bounce ideas and observations off one another is quite educational.

Their mission for the next several days is twofold.  First and foremost is helping Dan Rodriguez, the Texas State graduate student who is studying Kelley Cave and adjacent Skiles Shelter for his Master’s thesis. Last week Dan and fellow grad students finished digging a 1-x-2m unit in Kelley, or at least he took it as deep as they could practically (and safely) go – a bit over 7 feet deep. When the digging was done, Dan carefully cleaned several of the profiles (walls) and took many overlapping detailed photographs using LED light panels to illuminate the dark confines.  This week Black cleaned up the walls a bit more and sprayed them down with a fine mist.  Dan’s dry photos show some things well, but wetting the walls makes many subtle and obvious details ‘pop out.’  So we took another round of several hundred overlapping LED-lit close-up photos and through computer magic stitched these together to form geo-referenced mosaic and 3D model using the Structure from Motion (SfM) approach pioneered by our collaborator and archaeo-geek extraordinaire Mark Willis.  But we’ll tell more about Mark and SfM in future posts.

Today Frederick, Lawrence, and Rodriguez spent all day in and out of the Kelley Cave excavation unit, carefully and minutely examining the stratigraphy (layering) and spotting details neither the photos nor our archaeological eyes had seen.  Ken and Charles took turns in the hole, each annotating the printed photomosaics with their take on the layers.  Dan watched from above and annotated his own set, asking questions and trying to put the geoarch’s observations and explanations in the context of what his excavations had encountered. And we haven’t even mentioned the sampling.

Image

Ken Lawrence annotating the stratigraphic layers present in the profile.

We should explain that one of us was also present and madly taking notes.  I (Jake) have been tasked by Dr. B (Steve) to make myself useful to the geoarchaeologists, now and as the project unfolds. My minor at Texas State was Geology, so I have an inkling of what they are doing. Both Charles and Ken expressed that the Kelley profile is as complicated and messy a profile as they have ever seen. Their goal is to take as many samples as possible to try and deconstruct how all the sediment came to be in the shelter. According to Charles, the sediment could be alluvium from the Rio Grande, alluvium from Mile Canyon, soil from above the shelter on the canyon rim, and possibly even from swallow and mud dauber nests.

Ken began by taking samples from within the north profile’s different stratigraphic layers. Using a trowel he dug as far into the layers as he needed to fill the quart sized sample bags. Once Ken was finished Charles took several micromorphology samples called micromorph blocks. The blocks are handled with the utmost care, wrapped in toilet paper and tape to help maintain their structure. These intact cubes of sediment can later be impregnated with plastic, and once impregnated they can be shaved into thin sections for microscopic analysis. Ken and Charles hope to piece together the jigsaw puzzle of depositional processes within the rockshelter by analyzing the dirt’s composition. Today was the first step towards that end.

Image

Dr. Charles Frederick packaging a micromorph block.

Above we said that the geoarchaeological mission was twofold.  Part two is the big picture: how did the deposits within Eagle Nest Canyon form and transform over time and how did the landscape itself form and weather the passage of time?   OK, threefold: Charles and Ken are also here to help us strategize how we will investigate Eagle Cave, the biggest of the canyon’s rockshelters, over the next few months.  We have formed our basic research plan, but they will help us figure out how we can maximize the amount of data we can collect as we document and sample the rockshelter’s discontinuous stratigraphic profiles.  Data that will speak to the big picture and inform us as to the nitty gritty.  Stretching before our research eyes are many forms of dirt by other names.

 

Expedition Collaborators

By Steve Black

Archaeology is inherently collaborative, especially on a major project like the Eagle Nest Canyon Expedition.  And that for me is a cat’s meow – building and working closely with a stellar set of collaborators. For us it starts with the landowners, Jack and Wilmuth Skiles, who for over 60 years have protected the archaeological sites we have the privilege of studying. Their house overlooks the canyon and they follow our progress closely, helping in every way they can.  Jack’s 1996 book, Judge Roy Bean Country, tells the history of the area through colorful vignettes he learned by interviewing old timers and digging into old newspaper accounts and court records.

Readers of this blog have already met or will soon meet our core crew members as they take turns making blog entries and add a bit about themselves.  Today is my day to chip in.  I am an assistant professor of anthropology at Texas State University in San Marcos, and I have been doing archaeology mostly in Texas since I was an undergraduate at UT-Austin in the mid-1970s. I am also one of the editors of www.texasbeyondhistory.net, where you will find several online exhibits on the archaeology of the Lower Pecos Canyonlands. If you are just learning about the area, start with the exhibit by that name, www.texasbeyondhistory.net/pecos.  For an introduction to our canyon, see www.texasbeyondhistory.net/bonfire/caretakers.html where you can learn more about “The Land and Its Caretakers” and take a “Virtual Tour of Mile Canyon.”  Eagle Nest Canyon is also known as Mile Canyon because it is about a mile from the mouth of the canyon to its abrupt ‘box’ head.  Back to our collaborators.

The Shumla Archaeological Research and Education Center is our key partner on this project.  Under the leadership of Dr Carolyn Boyd, the Shumla School has built an amazing program of hands-on education and systematic rock art research right here in the Lower Pecos. Shumla is based in Comstock and our field headquarters is the Shumla Campus on the Shumla Ranch along the lower Pecos River about 15 minutes east from Langtry.  Shumla is contributing to this expedition in many other ways.  Two of our crew members, Jeremy Freeman and Vicky Muñoz, are Shumla staff members who are ‘on loan’ so to speak as part of Shumla’s Border Canyonlands Archaeological Project.  Shumla also loans us critical equipment such as a total data station and helps provide field transportation.  Our partnership with Shumla helps underscore the multi-faceted nature of Lower Pecos archaeology – the rock art on the rockshelter walls and the chewed up lechuguilla quids we find beneath the surface are part and parcel of the ‘whole enchilada,’ meaning the lives of the Indians that called the canyon home for so many generations.

In future entries we will introduce many of our other collaborators, such as the visiting experts who are taking part in our research project and our fellow archaeologists who come down to volunteer.  This week, for instance, retired archaeologist Daniel R. Potter is lending a hand and keeping the crew entertained with jokes at my expense.  “Steve, you need to put your hat back on—the glare off your dome is ruining the photo.”  Tomorrow geoarchaeologists Charles Frederick and Ken Lawrence will help us unravel and sample the complicated depositional history revealed in the stratigraphic profiles we have been exposing.  Like I said, working with so many wonderful collaborators is the cat’s meow!  (And I don’t mean the plaintive cry of Mystery, a young feral cat that has appeared in the canyon and demands sustenance—cheese sticks don’t seem to do the trick.)

Image

Jake, Brooke and Bryan overlooking the Pecos on Shumla Ranch

Cave Dust and A Feral Kitten

 

Week two is getting off to a great start in Eagle Nest Canyon. Mother Nature has graced the expedition team with warm weather, clear skies, and fairly low winds. Due to the NE aspect of Skiles Shelter, it gets quite warm in the afternoon so the team has been using canopies to shade the units from the sun for photography and personal comfort. One of the obstacles the team has been facing is how to properly dispose of the large amount of cave dust and loose sediment being exposed during excavation. In order to protect the paintings that line the back wall of the rock shelter, our screening station is below the shelter on the canyon floor. Screening at the base of the shelter eliminates much of the dust circulating around the shelter and prevents the dust from caking on the paintings. The team has also been wearing respirator masks throughout the duration of the work days. If our lungs could speak, they would be thanking us.

 

As for the progress of our excavation, Brooke, Jeremy, Tina, and Jacob have uncovered several diagnostic projectile points from two of the four units that the team has open now. Among the points, the team has also been recovering charcoal, chert flakes, fibrous plant material, bone, and burned rock used in earth ovens. It will be exciting to see what other cultural material lies beneath our feet.

 

Recently the expedition team has acquired a new member. A small orange feral kitten has curiously made its way down into the rock shelter. Dr Black named the kitten “Mistake” after he realized feeding it would only encourage it to stay around.  Getting the cat out the canyon before it becomes prey is an ongoing work in progress. We will keep you updated.

 

Bryan Heisinger

cat

 

 

 

Second Day of Work at Skiles Shelter

 

My name is Tina Nielsen and I am a first year graduate student at Texas State University and the Laboratory Director at SWCA, Inc. in Austin, Texas. This semester I have the unique opportunity to participate in the ASWT project in the Lower Pecos. I will be managing the field laboratory in addition to conducting field work and helping with many other aspects of the project. I look forward to teaching the interns about lab processing, analysis, and curation and look forward to the many challenges the spring semester holds.

Today Jacob and I continued excavating the disturbed layer (Layer 1) in Unit D at Skiles Shelter. Just when we thought we would never get past the endless amount of goat poop, we finally began hitting the underlying flood deposits. To make this accomplishment even sweeter, we found our first arrow point of the project at the contact between Layer 1 and 2! After we did the necessary paperwork and photogrammetry, we began excavating the flood deposit and surrounding matrix. Almost immediately Jacob found a sexy (many archaeologists actually use this term to describe artifacts, I promise) teardrop biface in situ. Just after, I found a Perdiz Point on the screen. Now, archaeology is not just about finding goodies, but as the sun starts beating down on you after many hours of digging and hauling buckets up and down the hill it is a nice reward.  

ImageImage

Dr. Black, Brian, and Charles finished working on profiling Unit A/B and Vicky, Jeremy, and Brooke opened up a 2×1 meter unit (Unit E) south of Unit A/B on the talus slope of the shelter. All in all, it was a very productive day at the site!