Four Corners Research-Archaeology in the Mesa Verde Region

The Mitchell Springs Ruin Group was originally noted by Lewis Henry Morgan in 1876 during his study of early Americans of the American Southwest.  He described the site and noted what has been referred to as Morgan's Tower which still stands near Mitchell Springs.  Morgan remarked that the largest mound in the group stood 10 or 12 feet tall and measured 94 feet by 47 feet.  This structure was obliterated by pot hunters with a bulldozer in 1977.  During a reconnaissance of the San Juan Watershed in the 1890's, T. Mitchell Prudden mentioned the site and provided a description and assessment of its conditione.  Several years later, he returned, and with the assistance of Clayton Wetherill and Henry Hun, conducted archaeological excavations related to his study of what has been referred to as unit pueblos or Prudden Units. 

Can't touch 'dis.....Effigy Vessel from Mitchell Springs - Pueblo A greathouse Room 18. Note prominent man-package.
Embedded anvil stone in Structure 25.  To the left of this stone are the right and left radius of a linx that were lying beside a ceramic 'cloud blower' pipe. On the east side of the stone a very large heirloom archaic projectile point was pointing west. It was over 4 cm wide and tall. On the north side of the anvil stone, an Abajo Red-on-Orange feather box was placed.  West of the hearth were two hide-bound shaped-stick mats or possibly altars.  On them were large baskets full of corn kernels and pottery vessels containing very large ears of corn. 

With approximately 30 sq. meters of floor space, Pitstructure 25, while small in comparison to many great pitstructures of the day, was about twice the size of a middle ninth- century household pitstructure. Its size and contents suggests it may have functioned more as a ritual structure than a household pitstructure despite the obvious intensity of corn grinding operations.
Mitchell Springs Group
Structure 26 Basketmaker III pit room abandoned in early to mid 8th century. This is one of many structures built under and around the Pueblo A greathouse. 
Room 27, located near the NW corner of Pueblo A, this room contains features typically found in both surface living rooms as well as pitstructures of the 9th century in the Montezuma Valley. Features include an embedded anvil stone, bins, sand filled pits, sipapu, and a floor vault
Map of known structures inside Sector 7.  The construction of Pueblo A began by A.D. 1000-1050 (purple walls).  The above ground central kiva and the 2 large squarish rooms (lime green walls) were added in the mid to late 1000s or very early 1100s. The outer wall of the tri-wall and the tall single story rooms (the red and the blue walls) were apparently added in the early 1100s. 

The greathouse was built into the plaza of an 8th or 9th century roomblock and almost certainly overlies pit structures from that era.  Eleventh century rooms were incorporated into the final version of the greathouse and the rear half of the pueblo was 2 stories tall which is on the early side for this type of construction in the Mesa Verde region. The tri-wall structure was appended onto the west side of the great house. In the innermost chamber of the tri-wall is a Chaco style kiva and beneath that kiva lies a kiva that was built in the A.D. 900s or 1000s.
1938 aerial photo showing multiple water courses draining into the Mitchell Springs Community.  This created one of the most productive farming zones in the Montezuma Valley and as such would have attracted maize farmers for centuries. Control of the upland watershed probably took place when use of water control features in the 9th-11th centuries allowed water to be taken out of the drainages and spread onto the land between the water courses. Unit pueblo construction along these drainages boomed in the A.D. 900's. A very large population already made this area home during the Pueblo I period as more than 1,000 linear meters of roomblocks are spread over a 2 square mile area around the central Mitchell Springs community.
Tri-Wall Kiva C lies directly beneath Tri Wall Kiva B.  Although this structure is round, it appears to date to the early A.D. 900s. Like Kiva B above it, Kiva C contains no pilasters or roof offsets.  It resembles a tube in shape and contains no masonry in the original construction.

Look carefully at the plastered wall in the photo and you can see an etched drawing on the walls.  A horizontal line (dato) encircles the kiva and has appended triangles. This pattern closely resembles the painted mural that was plastered onto Kiva B above it.  These two structures may be over 200 years apart in age yet both structures resemble each other in shape, features, mural design and building location.
The only ground floor entrance to Pueblo A was through this corner doorway in the south end of the pueblo.  Corner doorways are rare and are usually found inside greathouses.  A massive stone slab was found on the floor just inside the room.  It would have been made by a master mason as this stone weighed over 100 lbs and was the same thickness across the slab (10 cm).  The pueblo burned and the resulting collapse brought down the entire front of the structure at one time.  These walls were still articulated and confirm the single-story rooms stood over 3 meters tall.  The back rooms were 2 story rooms.  Note the door sill of embedded wood beams.
Structure 26 Basketmaker III pit room entryway through upright slabs. Note step.
Pueblo A - Room 18, is a ground floor room that was part of the original 8-room greathouse.  It was probably built in the mid to late 11th Century and last used in the early 1200s.  The entire pueblo was destroyed by a fire at around 1225 A.D. The room above this one, fell into Room 18 and portions of the 2nd story floor were found intact,
​Pitstructure 25 burned along with the possessions of those who used it.  The floor was prepared for the final act of deliberately setting the building ablaze. Accelerants were systematically used for this purpose. Without multiple simultaneous fires and oxygen access, it was not an easy process to get a pitstructure to catch ablaze. A dense collection of high-input items were destroyed in the process.
500 Years of using and reusing the same physical space.  Clearly this was a power-point that was recognized by more than 20 generations of Puebloans 
Great Kiva Plan View - This structure was built into the courtyard of the largest recorded greathouse at Mitchell Springs.  Noted in 1870 by Lewis Henry Morgan, an early ethnographer and archaeologist, this greathouse, one of 4 at the site, was at least 2 stories tall by Morgans description. It was roughly mapped in 1976 just prior to its obliteration by a well-known local pothunter. 
Turtle back adobe shaped blocks were used to build the east wall of Room 47 as well as several other rooms in this room block.  This room lies beneath the outer chamber of the Tri-Wall and dates to the early 800s.  The wall stood a minimum of a meter and a half tall.  Room 47 contains many features that are ordinarily found in protokivas such as a complex sipapu, an ordinary round sipapu, and numerous oblong or oval green colored sand filled pits.
Colorado Archaeological Society 80th Anniversary,Power Accumulation, Expression and Transfer at Mitchell Springs
Northwest corner of Pueblo A with Room 7 at upper R in photo.  Tri-Wall outer chamber meets the pueblo at bottom of photo.  Strata test at upper L is EU 37. Early deposits from Pueblo I and Basketmaker III filled borrow pits at bottom of this test. 
​SE corner of great house Pueblo A looking north.  Testing of Pit Structure 28 (bottom), Kiva E (top), and Pit Structure 25 (right).  From drone, Field School Aug 8, 2017

Great House Pueblo B, Court Kiva, note masonry style (similar to Type I masonry in some Chaco Canyon great houses) at the remodeled southern recess
Pizza and conversation with fellow sophisticates after work.  Nothing tastes as good as pizza and beer after a day in the field...well..other than a big steak and a big beer.  Add a little entertainment and we have a party!
Kiva D masonry from floor level to top of bench.  Tabular stone in this style was incorporated into the penultimate addition to the great house Pueblo A.  As is the case with all of the kivas in Sector 7, Kiva D contained no pilasters or floor mounted roof supports.  This kiva was built around A.D. 1000 and abandoned at about 1080 or 1100. 
Pueblo A began as a 2-story 16 room building at approximately AD 1050 (black walls).  This is a small multi-story great house that reached it's greatest size at approximately AD 1130 (shown in overlaid photo)
Georeferenced survey grade accuracy from drone
Learning about the ceramics that came from some of the excavation units at Mitchell Springs during the 2016 field season.
Examining potential tree-ring specimens from Structure 25.  In 2016, Dr. Spear a dendrochronologist from Indiana State University (right) brought her students and worked with Steve's regular field school from Eastern Illinois.
Mitchell Springs community core  circa AD 1100
Mitchell Springs community core
 AD 825-875
2018 Mitchell Springs Field School.  Campground and Mesa Verde in background
Construction sequence related to the tri-wall building which is attached to the west side of greathouse Pueblo A.  Excavations have focused on identifying the various construction episodes in this part of the site which began at around AD 650 and continued through about AD 1240. .