Fall is always a busy time of year for field archaeology in the Northern Southwest. Final documentation of open excavation units and prepping some to remain open during the winter months is a lot of work. The Sector 11 great kiva will be backfilled and the Basketmaker III pit room discovered in 2013 and located near the northeast corner of Pueblo A will also be backfilled. This structure, designated as Structure 26 was originally constructed to serve as a grinding room/storage space but in the final days of its life, a thermal feature was installed in the accumulating floor fill. It isn't clear if the function of the building changed at this point. The roof was constructed by placing bent green lodge poles against the inside of the upright slabs that formed the boundary of the room. On the top of these poles, a layer of adobe, brush and small stone slabs coated it. The door was built on the south end where an adobe lip prevented drainage from entering the pit building. This ramp type entry featured a large flat sandstone slab as a step. The bell shaped floor pit probably held the processed materials for short term storage. A pit cover slab and metate were located nearby. We'd like to know more about the Basketmaker III presence in the Mitchell Springs Community but the intense occupation in subsequent times appears to have obscured the architectural evidence. Surveys and excavations indicate that a substantial population lived in and nearby during this period. Joel Brisbin reported (1971) that a large Basketmaker III structure existed on the north side of the main village inside the City of Cortez. Another large circular structure dating to this period or Pueblo I is located nearby.
In the ninth century the population of the 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. Three greathouses and two 10+ meter kivas were constructed at the village center starting at around A.D. 1050. Within 75 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 defendable locations with a source of fresh water and nearby arable fields.
Our work inside Structure 25, located at the southeast corner of Pueblo A is winding down for the year. This building contains about 35 square meters of floor space and was probably used by a larger segment of the community rather than by a few interrelated 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, or flaked lithics were recovered south of the wingwall but 3 bone awls were evidently nested in the ceiling immediately to the north of the wingwall (see photo to 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 wanted or 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 four storage rooms on the east side of Pueblo A were single story rooms that stood over 3 meters tall. All of the remaining rooms were two stories tall. The central kiva was built with rectangular rooms above it so in effect, it was a room that was concealed by contemporaneously used surrounding rooms on all sides, including above it. During the partial excavation of Room 11 in the early 1990's, a subfloor test revealed the presence of earlier rooms beneath it, and beneath the central kiva. Excavations inside these two rooms are underway and will continue in the Summer of 2015. Both were fully lined with masonry and were probably built in the early 12th century.
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 probably 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 material that had been applied to the bench and bench back. This revealed 20 different layers of plaster that ranged in color from 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.......