Four Corners Research-Archaeology in the Mesa Verde Region

Four Corners Research ® 7823 Road 25, Cortez, CO 81321    970-565-8758   ​
West end of Mitchell Springs Sector 11 great kiva. Note western floor vault and double bench. Arrow scale just outside the center of vault is 25 cm long. Roofing a structure of this size is no small engineering feat. The floor and roof were rebuilt and replaced at least twice.
Mitchell Springs Pit Structure 6 is approximately 8 meters across. It was set ablaze without salvaging useable roof beams. The Sector 11 great kiva was built over the top of it.
Approximately 80 Tree-Ring were collected from the burned roof of Structure 46 at Champagne. .
The MS great kiva was built over the top of a burned over-size pit structure that was built in A.D. 787.using many beams from an earlier structure that was built in A.D. 757  Note adobe column-like veneer at the bottom of NW main roof support post..
One of several quartz crystals from the west end of the MS great kiva. Hundreds of shell and turquoise beads were found in the upper and mid fill.
Shell and turquoise was quite abundant in the Mitchell Springs Sector 11 great kiva fill.
Knife blade from floor of MS Sector 11 great kiva, from beneath floor ramp feature near the western floor vault.
Portion of the south end of Mitchell Springs Sector 11 great kiva tested in 2002.
Turquoise bead from the floor fill below the roof of the MS great kiva.
Kiva 3 circa A.D. 950.  This structure incorporated an unusual SW ventilator. Note the masonry style of this early kiva. The wall niche at center-right in photo measures almost 25 cm across.
Small MS great house (Pueblo B) showing areas tested. This structure contains a 10+ meter diameter court kiva and multi-story construction.  Thick dashed line delineates the exterior of the building. A second kiva is located in the center-left of structure and was rebuilt in the 13th century.
Glendale College Field School working in the western end of Sector 11.  Excavations tested 8 surface rooms and 3 pit structures or early kivas. This area of the site was occupied during the A.D. 850-950 period.
Excavators working on Seg 9 of Room 1 on the east end of the North Hill at Champagne Spring. This and other structures in the immediate area were abandoned around A.D. 950-1000.
Randi taking a short break from her work in Champagne Spring Structure 37. In an unusual kiva closing ritual, numerous animals were simultaneously buried inside and around a stone cairn feature which stood more than a meter tall.
Below the Champagne Spring site in Squaw Canyon, this interesting petroglyph panel contains several mountain lion figures.
Sketching the floor plan and floor features of Structure 46 at Champagne Spring. The floor had unusual floor grooves and 5 sets of paired post holes. Some of these may have been used to anchor altars that could be moved during ceremonies. Note burned roof in strata,
Structure 37 during excavations in the south end of this kiva. Over 40 animals were sacrificed and then buried. The work is very slow due to the heavy amount of documentation and cramped working conditions.
T.Mitchell Pruden making notes  by "Unit 1" at Mitchell Springs circa 1914
Click on an image above to enlarge
This web site was created to function as a repository for information and photographs generated during research and survey projects performed by Glendale Community College, Scottsdale Community College and Paradise Valley Community College from 1988-2004.  Subsequent research conducted by members of various Chapters of the Colorado Archaeological Society will also be posted here.  Many of these members have decades of experience in the field and laboratory.  Over the last 23 years, we have conducted private property survey's of the Mitchell Springs and Champagne Spring community's.  As time permits, earlier publications and reports will be linked for easy access.  Current research involves test excavations at the Mitchell Springs  Ruin Group and Champagne Spring Ruins.  We are also working on a project that explores the chemical composition and trade patterns of San Juan redware in the Mesa Verde region and SE Utah. 

More information can be accessed by navigating to the links to the upper left of this page.   

Many thanks to the Verde Valley Archaeological Center and the Arizona Archaeological Society for all of the help.

Oversize Pitstructure 6 - A 60+ sq meter building under the Sector 11 Great Kiva.  Note sculpted column treatment built around base of NW roof support post

     Our first session of the 2015 season wrapped up on May 4 and everyone seemed to have a lot of fun.  The weather was ideal.  Work continued on Structure 25 which was burned and abandoned around the middle A.D. 800s.  Part of our research involves the prehistoric process of decommissioning structures and features upon abandonment.  This process takes several forms but burning is the most common method.  In most cases, structures were 'cleaned' prior to abandonment but sometimes, a variation of this process leaves the user's tools and other possessions in place at the time of burning.  Structure 25 was 'closed' by the latter and we are taking the opportunity to study the process more closely. 

Winter preparations of the exposed  portions of the tri-wall and Pueblo A has led to some new and interesting discoveries over the last few months.  In 1988 and 1989, tests of the tri-wall revealed an unusual architectural configuration that is somewhat different than what can be gleaned from the 4 or 5 known to exist.  Vivian's (1959) seminal work on these enigmatic buildings is the only published work that I know of on tri-wall's that also involved excavation.  He and his associates used relatively modern excavation and recording techniques for this work.  No others have been tested or excavated since. Vivian tried to rebuild the record from earlier excavations that had been performed on the Pueblo del Arroyo great house tri-wall in Chaco and the Mound F and Hubbard Mound tri-wall at Aztec with limited success. Most known tri-wall's consist of three concentric walls; the innermost being the smallest circumference and the outer, the greatest.  The chambers created by the concentric walls were often further divided by cross-walls creating compartments that are generally featureless.  It is likely that these chambers held perishable products however, all excavations were performed before pollen and flotation techniques were developed so at this point, no proof has been detected to confirm this.  It is known however that whatever may have been stored in these chambers was gone by the time excavators had an opportunity to examine the deposits.

    Vivian concluded that the innermost concentric walls of both Mound F and the Hubbard Mound at Aztec as well as the del Arroyo tri-wall contained a building similar to the kiva.  Our 1988-89 studies at Mitchell Springs revealed a structure that is somewhat different than these in that the inner chamber appeared to have performed as a platform used for burning large fires. Last month, during tests inside the eastern half of this portion of the structure, evidence to suggest the existence of an inner tower was found. Unless the interior features of the 'tower' confirm the existence of a kiva, the Pueblo A structure would by definition be a tower.  If a kiva is confirmed to lie within the interior chamber, this structure might be considered a tower kiva. To date, a bench coated with multiple coatings of red, white and gray layers of plaster, an adobe floor, and one large masonry lined floor vault have been documented.

    We are taking a closer look at the Mitchell Springs tri-wall in an effort to add more modern data to what is currently known about these buildings. To my knowledge, all known tri-walls except the one at Mud Springs are on publicly managed lands and it is unlikely that any excavation or productive analysis will ever take place on these until at least A.D. 2275 or beyond.  Over the last 3 months, many new discoveries have been made during the process of exposing the tops of the walls of Pueblo A and its appended tri-wall.  We are preparing a manuscript on this work and it should be ready to submit for publication later this year.

     In the ninth century the population of the Mitchell Springs Community exploded, growing to many hundreds of rooms and setting the stage for the entry of the Chaco System and the construction of  new public architecture.  Four great houses and two 10+ meter kivas were constructed at the village center.  Within the course of less than 100 years the Chacoan System had collapsed leaving diminished population levels in the Mitchell Springs community.  By 1230 or 1240 A.D. the community and large portions of the Montezuma Valley became depopulated.  People consolidated into fewer and generally larger villages and defensible locations with a source of fresh water and nearby arable fields.

     Structure 25 is located at the southeast corner of Pueblo A.  This building contains about 30 square meters of floor space and was probably used by a larger segment of the community rather than by a few interrelated or cooperating  families.  Domestic activities were still conducted inside this structure although this aspect is still under investigation.  On the south side of the wingwall, the grinding of food and possibly other items was performed.  Although 14 manos and 6 pecking stones were stored there, only one metate was left in this part of Structure 25 when it was set ablaze.  Almost no bone byproducts, bone tools, debitage or flaked lithics were recovered south of the wingwall but 3 bone awls were evidently nested together in the ceiling immediately to the north of the wingwall (see photo above left).  A hafted axe hammer, a large core, 2-hand polishing stone and a small abrading stone were also stored in this area of the structure.  Fragments of mats and fabric were collected from the floor just north of the ventilator opening and in the east section of space just south of the wingwall.  More than 300 tree-ring samples were processed from the burned roof.  At this point in the excavation, it isn't clear if the robust artifact assemblage indicates that tools were deliberately left in the building when it was burned because they were not needed or for reasons possibly related to the ceremonial closing of the building.

     Thanks to Joel Brisbin and Gay Ives, the complex stratigraphic profiles exposed by the excavation units inside the Sector 11 great kiva were documented and photographed. As part of my research questions related to the construction of special buildings on top of earlier special buildings, an early great pit structure built in 758 A.D. was tested. During excavations in the south and west ends of the great kiva the Structure 6 over-sized pit structure was discovered. It contained approximately 65 square meters of floor space and was ceremonially closed by burning immediately after abandonment. Just as we see in Sector 7 Structure 25, a large assemblage of usable tools, fabric, human hair twine, mats, baskets, ceramic vessels and ornaments were left on the floor when the building was intentionally burned in the late 8th century. In the mid to late 900's, a great kiva was built over it and was subsequently rebuilt at least two other times before being abandoned in the 1130's or 40's. 

     In Pueblo A , an effort to emulate a construction style which had roots in Chaco is apparent in the preplanned footprint of the pueblo as well as some masonry style characteristics incorporated into some of the rooms.  The front two rows of storage rooms on the south end of the pueblo and the 3 or 4 storage rooms on the east side of Pueblo A were single story rooms. In one event, the burning pueblo's southern wall fell southward and because it was still articulated, it was documented to be a little over 3 maters tall.  The southern two rows of rooms were added to the original configuration of the Pueblo, after the Tri Wall structure had been appended to it.  All of the remaining rooms were two stories tall.  The central kiva may have been built with rectangular rooms above it so in effect, it may have been a round, masonry enclosed structure that was concealed from view because contemporaneously used rooms surrounded it on all sides, including above it.  During the partial excavation of Room 11 in the early 1990's, a subfloor test indicates the likely presence of earlier rooms beneath it, and beneath the central kiva.  

     Another interesting item in regard to the preplanned footprint of Pueblo A is that only two of the 22 ground floor rooms were habitation rooms. They are the only square shaped rooms in the pueblo, a trait that was also found at Salmon Ruins in Bloomfield NM. The second story rooms above these two rooms were also used for domestic activities such as cooking and sleeping but were evidently not used for grinding operations.  Both the upper and lower floor rooms were directly connected via roof hatchways.  In the Summer of  2015 or 2016, the area on the west side of the west wall doorway in Room 18 will be tested to determine how that space was used. 

  Kiva A has been a fascinating bit of discovery. Some of its masonry is of a finer style than appears to be the norm at Mitchell Springs. Like Room 18, Kiva A also burned in a cataclysmic fire that ended the occupation of Pueblo A and possibly the entire Mitchell Springs Community. It has no southern recess which is not the norm for kivas built and used during this time period in the Montezuma Valley.  In the space that is often reserved for a southern recess, an elaborate ventilator feature was engineered and constructed. This feature brought fresh air down into the kiva chamber from either the floor of the room above it or from atop Pueblo A.  The pressure differential between the dark spaces in Kiva A in the belly of the pueblo, to the sunlit intake point 20 feet above (on the roof of Pueblo A), would have created a natural circulating cooling effect in the summer months.  Regulating the airflow into the ventilator would prevent too much cold air from entering during cold nights.  On one of the masonry stones that was used to create the elaborated ventilator feature (see photo below Left), an interesting petroglyph was carved.

​     A very thin bench was located and a test to confirm it was indeed present removed a 4-5 cm thick section of the plaster that had been applied to the bench and bench back. This revealed 20 different layers that ranged in color from bright white to red to gray. Next season the bench will be be uncovered and we should get a look at some of the Kiva A floor.  It'll be a gas.

See Mitchell Springs Tab for more information on this work.......

Mitchell Springs, Tri-Wall Kiva B bench mural.  Many coatings of plaster survived 800 years underground.  The final coating was white on the top half of the bench bottom and red at the bottom half.  Small red dots were appended to the top of the red plaster coat.
Eastern Illinois University Geology and GIS Class working at Mitchell Springs with Mesa Verde in background.
​Profiling the hearth of the Tri-Wall kiva.  This unusual configuration consisted of a masonry lined cylindrical feature that was almost 40 cm deep.  The more common hearth configuration contains no masonry, is basin shaped and 10-15 cm deep.
Last version of the Mitchell Springs Tri-Wall Kiva B was appended to the west end of Pueblo A, a small 28-room 2-story greathouse.  Articulated fallen walls confirm this building stood more than 5 meters tall. It had no pilasters or visible roof offsets and despite the tallness of the kiva, only one roof was found laying on the floor. The outermost chamber was probably not as tall as the kiva or middle chamber of the tri-wall.  Note jagged stones above the bench.  This masonry is from the original tower that was built in the 900s.

The last activity inside this structure was the destruction of a large portion of the NE quadrant as well as the east and south wall of the floor vault. After that, it was sealed from further entry until the roof and walls collapsed.
Mitchell Springs Sector 11 great kiva (west end). Note complex stratigraphy evident in excavation unit walls. These fill layers contained hundreds of beads and other completely functional tools and projectile points suggesting their use as offerings.
I sure appreciate the hard work and the conscientious way all of you go about doing it.  We like to have fun out here and our friends who have supported these projects over the years have made that possible!  See you in August.
Fall is a beautiful time to be in the Four Corners area.  View from the center of the Mitchell Springs Community looking toward Mesa Verde.
2015 Field School Dates

July 31- August 3                     August 14-17                 September 11-14

Subfloor ventilator in the tri-wall Kiva B at Mitchell Springs.  It was replaced by an above floor ventilator in the late A.D. 1100s.  Note the unburned wood that covered this masonry feature.  Two of these members were collected for tree-ring samples. The Chaco-style bench recess was retained.
Lunch time under the big tree.  Several years ago, this tree was documented as the largest cottonwood in CO
Mitchell Springs Tri Wall Kiva B, original version with Chaco style features
Original version of Tri-Wall Kiva B with earlier Tri-Wall Kiva C visible beneath (see final version of Kiva B at Left).  Kiva C was round, contained almost no masonry, and had no bench or pilasters.  It appears to date to have been abandoned in the A.D. 900s.

At abandonment, the room was cleaned and the roof was dismantled and collapsed onto the floor. Immediately thereafter, it was partially filled with the roof of another structure and redeposited sterile soil. The walls would have been deliberately covered in order for the preservation of the mural etchings to have survived for 1100 years.  
Structure 25 at Mitchell Springs, excavating in the SE corner of this protokiva.
Two burned baskets were exposed on the western side of Structure 25.  Both contained ears of corn or large bulk kernels.  Some of these ears were almost 15 cm long which is on the large side for this period of time. Atop Basket #1, was a very large re-constructable San Juan redware bowl and beneath the basket were 20-30 shaped sticks that may have been lashed together with an organic material that looks a bit like leather.