Sunday, June 30, 2013

One week after Solstice


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Excavations on Friday (June 28, 2013) brought some surprises.  We reached the bottom of our 11th 20 cm level, meaning that we have now excavated 2.2 m below the surface.  It’s getting harder to get in and out of the room.  The eastern wall of the room does not really appear in the photographs from Pepper and Wetherill’s excavations, so we were uncertain what this wall would look like, especially in the SE corner of the room.  We knew that the partition wall between 28 and 28A was about 1’ wide (according to Pepper) and masonry.  On Friday, we uncovered a post-reinforced adobe or plaster wall directly in front of the masonry wall (see photo below).   The tops of the post holes were filled with ash, but the slightest tap and the ash fell into a seemingly bottomless hole.  Measurement with a carpenter’s rule revealed that the postholes are 1.2 meters deep!  It feels as if there is a flagstone at the bottom of each.  In the SE corner of Room 28, two flat stones are positioned—there was burned daub atop them, so it is likely they are actually part of the wall, but they are definitely shaped stone.  
Postholes in partition wall between Rooms 28 and 28A.  Note flat stones in SE corner of room.
Work in the western part of the room revealed several surprises.  A mass of burned material surrounded a glass bottle.  Our resident historical archaeology expert, crewmember Leigh Cominiello, is working on finding out more about the bottle and its contents.  The bottle, two rusted cans, and several nails constitute the historic artifacts we have found.  Along the south wall of the room, about midway between the west and east walls, we encountered a wooden plank that is over a meter in length.  The plank is in good condition.  Because Pepper did not describe finding any planks in Room 28, the recovery of this plank helps confirm that Room 28 was backfilled with material from another room or rooms.  Nearby were two other pieces of wood, probably posts or roofing material.  We took all of these for identification of the wood and possible tree-ring dating.  Having read about planks in Pepper and Judd’s volumes on Pueblo Bonito, it is instructive to see how uniformly shaped and thin they are.  It is hard to imagine creating these with stone tools.
Near the center of the room, we found a complete trough metate.  It is in excellent condition, but Pepper and Wetherill probably decided it was too cumbersome to ship back East and left it in the room.  
Base of Level 11 in Room 28.  Note the beautiful screw-jacks!  The metate is visible in the center of the photograph. 
I believe we are now within about 20 cm of the surface where Pepper and Wetherill found the cylinder jars.  The matrix is sandy loam, but there are lots of rocks just beneath this level, so the next level may take some time to excavate.  Note our two new screw-jacks, which provide novel ways to challenge our hard hats! 

Thursday, June 27, 2013

Room 28: The Movie


If Room 28 ever becomes the subject of a movie, the trailer would go something like this (and please read with a really deep voice):
In a World made of sandstone, nothing is what it seems.  Only the rough survive. 
Anyone who has worked in Chaco can verify that sandstone aspires to be anything but a rock.  It tries hard to look like broken pottery, chipped stone, and even shell.  It was the most common stone used for groundstone artifacts, such as manos and metates, in Chaco, and yet most of the time sandstone is just sandstone.  Sometimes it was shaped for use as masonry or for features (hearths, hatches).  And sometimes it was actually used as a groundstone artifact.  Figuring out which pieces of sandstone are actual artifacts takes some time and experience.  We have now removed at least six wagonloads of non-artifactual sandstone from Room 28 and it is clear that there is still much to remove.  Pepper and Wetherill apparently preferred to throw lots of rocks in front of doors as they backfilled.  Part of the room is sandy loam and easy to excavate and the rest is a tangled mess of rocks.  We are getting closer to the floor, but still have about 20-40 cm to go before we reach the level where Pepper stopped digging.
One filled doorway collapsed yesterday, with rocks filling the upper part falling downward into the lower part as we cleared it.  We were clearing it to have one of the NPS crew members, Harold Suina, fill it with new masonry to keep it from collapsing.  And then part of it collapsed.  He is truly a master mason and did a beautiful job building a new filler for the door.  This will then be covered with yet another screwjack and plywood to hold the opposite wall in place.  The other two doorways in Room 28 are not faring much better. The doorway in the NE corner has a collapsed lintel, so we can’t work in that area at all—the entire wall above it might fall.  The doorway in the NW corner also has a fallen lintel—this time made of wood instead of stone, so we are carefully avoiding the area until we have excavated the rest of the room. 
Harold Suina fills the SE doorway of Room 28 to keep it from collapsing.

Level 10 completed for Room 28.  Large balk on right is to protect collapsed NE door to Room 28.  Smaller pedestal at northwest corner of room is to protect door into Room 32.  Burning is evident on south wall of room.  The stratigraphic profile clearly shows the backfill thrown against the south wall by the Hyde Expedition. 

We had a lot of visitors yesterday.  The UNM Department of Anthropology Staff visited: Jennifer George, JoNella Vasquez, Carla Sarracino, Ann Braswell, Matt Tuttle, and Joanne Kuestner visited the site, followed by a crew from the Office of Contract Archaeology led by Kevin Brown, then Cottonwood Gulch, then the Campfire Boys and Girls, and finally a group from the University of Georgia (led by John Kantner).

Tuesday, June 25, 2013

Little Room in the Pueblo


We returned to the excavations in Room 28 at Pueblo Bonito today after a hiatus.  The complex way in which the room was backfilled continues to surprise us.  In the NW corner of the room, we continue to find charred roofing beams suitable for tree-ring dating (although we don’t know exactly which room they came from).  In the SW corner, there is a clear area of sand that may be: an unexcavated area left by George Pepper OR blow sand that filled a void in the room once it was excavated OR blow sand from some other room thrown here by Pepper as he excavated adjoining rooms.  This area is easy and fun to excavate.  The center of the room from west to east is filled with rocks—masonry from some place, often with air pockets between the rocks.  The rocks seem endless—the Park Service provides a wagon for the rocks and takes them away to use in stabilization activities.  They have hauled away five or six wagon loads of rocks so far.  
Panorama view of excavation area.  On the left, screens set up on top of a tarp.  In the center, stabilization crew carries plywood by little green wagon filled with rocks from the excavation.  To the right, the gray 'garage' covering Room 28. 
The NE door, which led into Room 51A has largely collapsed—the lintel is broken and leaning at a dangerous angle.  So despite our interest in working in this area, it is too dangerous to remove any more supporting dirt in front of the door.  The door to the plaza, located in the SE corner of the room had been filled with rock at some point in the last hundred years—just in front of the door is an iron can surrounded by rock, all clearly located within a pit.  The entire feature may have been placed here to support the rocks in the door.  This was a door that had steps that led up into the plaza adjacent to Room 28.  Because of the rocks filling the door, we will have to forego excavating the door further—once again, it’s too dangerous.  Another screwjack will be placed from door to door on the eastern end of the room sometime in the next couple of days.  We are getting a lot of exercise bobbing up and down around the screwjacks.
As we get closer to the area where George Pepper found the cylinder jars, we have begun screening everything with 1/8th inch mesh and some areas with windowscreening.  It takes longer to screen this way, but it ensures that we aren’t missing artifacts and fauna in the screens.  Dr. Wills located a corncob in the screen today!  Only our second in this room. 
Some friends in Alaska graciously sent us a vintage game called Mr. Bucket to play in our spare time.  We appreciate the opportunity to spend more time with buckets.  Thanks to Will and Mark for the excellent gift!

Saturday, June 15, 2013

Another Friday in Pueblo Bonito


After someone broke into the excavation area, the Park Service has asked that we keep comments about what we are finding to a minimum.  So we will primarily talk about the architecture and fill we are encountering here.  Those of you who have read previous posts may notice that they have now been updated to remove mention of artifacts.  Because we are still in the backfill in Room 28, we are finding mostly broken pottery and chipped stone—nothing out of the ordinary for Chaco sites of this time period.  However, it has become clear that the backfill we are digging through includes primarily fill from Room 28, with some mixture from adjacent rooms.
We seem finally to be getting to the bottom of the burned material—there is much less charcoal and burned daub in the 8th layer we are currently excavating; 8 layers means we are now excavating down to 160 cm from were we began two weeks ago.  The complex system of screw-jacks in place make it hard to excavate, but our hardhats help keep our heads safe as we duck under the steel pipes! 
We have been starting the day at 7 AM, but will start earlier as it gets hotter.  It’s wonderful to be the first people out at Pueblo Bonito— the birds and animals provide the only sounds.  Crows like to tease us from atop the Canyon wall.  Sometimes we encounter the elk herd in the morning before they find shade for the day. 
Friday was a busy day, with visits from the Sierra Club (led by Karen Grief), Steve Lekson/Cathy Cameron and their students, William Walker and the NMSU field school students, and finally Barbara West and friends. 

Wednesday, June 12, 2013

News from Room 28

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Things have been very busy in Chaco Canyon.  We have removed a couple more levels of Room 28, but are still working through the backfill from the 1896 excavations.  The work is slowed primarily by the presence of both charred roofing beams (literally hundreds) and burned daub (the material packed around the roofing material to create both roof and floor above).  Safety issues forced us to add two additional screw jacks crossing the room at 90 degree angles—so we now need to negotiate three separate steel pipes crossing the room—but they provide support from the walls of the room and ensure that we are safe.  We also have a security guard protecting the excavation when we are not present—and this turned out to be a good thing on Saturday when a man with a shovel sneaked into the excavation and was scared away by our security guard. 
Emily Jones, UNM faculty member and faunal expert, joined us on Tuesday.  She identified many of the bones we have recovered, including birds, rabbits, and rodents—many rodents!  It was wonderful to have the help and identifications of our fauna.
Some of the material we are finding suggests that the backfill we are digging is indeed from Room 28.  What a surprise if George Pepper somehow managed to return the fill of Room 28 to its original location after moving it around.  While modern archaeologists virtually always backfill with the dirt they remove from an excavation, Pepper's field notes indicate he excavated other rooms before backfilling Room 28 and that he used Room 28 to hold the dirt from those other excavations-- but perhaps only temporarily.  Ultimately, he may have succeeded to putting the Room 28 fill back where it came from.

Sunday, June 9, 2013

Ruminating on Room 28

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Room 28 continues to provide puzzles for us to ponder.  By Friday afternoon, we were well into Level 4.  This level is characterized by a series of strips with different characteristics.  Along the west wall of the room, the matrix continues to contain charred roofing wood and burned daub.  To the east, in the center of the room, is a strip of sand, followed further east by more burned material, and then a final strip of sand and fallen masonry.  The complexity of the level makes it difficult to excavate, so we ended the day having about five centimeters left to complete the level.  We have not yet reached the partition wall that Pepper found separating Rooms 28 and 28a—it should be somewhere under the wall fall.  We think it is possible that the wall fall came from a wall constructed to keep people from entering the room some time in the last century.
Some of the daub is fascinating, with impressions of the small pieces of wood used in the roofing as well as the knots used to tie them together.  The largest chunk of daub is almost a square foot in size and includes both the impressions of the ceiling as well as the plaster floor above. 
We are fortunate to be able to screen all material close to the room—we are screening onto a large tarp set up above Room 37, with four screens set up side by side—three are ¼” and one 1/8”.  We put the sandstone we find into two areas: some shows signs of use for ground stone artifacts (broken manos, metates, and other grinding stones).  The stones that were architectural, such as masonry blocks, are put in a wagon and will be used by the stabilization crew in repairing walls in Chaco.  The dirt we screen will eventually be returned to the room when we are finished excavating. 
Artifacts are not abundant in the fill—we generally find only 1 artifact per screen.  Sherds are the most common artifact type, followed by chipped stone, and then ground stone.  We also find faunal bone, which seems to be from small animals.  Faunal expert and UNM faculty member, Emily Jones, visits us tomorrow, so we’re hoping to get some IDs for the bones from here. 

Thursday, June 6, 2013

Room 28 continued

 
We’ve had a busy two days in Room 28 at Pueblo Bonito!  We have excavated about 40-60 cm throughout the room.  The western 2/3 is filled with burned roofing material—beams and daub (the plaster capping on the ceilings that also served as the floor of upper stories).  The charred beams are very well preserved, so we are collecting them, although we do not know exactly where they came from (except Pueblo Bonito, of course).  The burned daub has impressions from the beams and we are also saving many of these fragments because they can tell us a lot about roofing. 
Surprisingly, the eastern 1/3 of the room is completely different—it is filled with fine sand and large sandstone masonry blocks.  It is clear that a wall was built in this area at some time in the last 100 years and then toppled, probably on purpose, but left in the room.  We removed about 100 sandstone blocks and many more small chinking stones.  We do not know who built the wall or why, but it certainly has slowed our progress.  One thing about archaeology is that you can never be sure what you will find.
Partially excavated Level 3 showing abundance of wall fall on eastern end of Room 28.
In this photograph, you can see the charred material on the western part of the room (top of photo, taken looking west), and the wall fall on the east.  We had excavated part way through the level when this photograph was taken, so the entire room is not down to level yet.  This photograph is taken looking in the same direction as Pepper's historic photograph of the room in our first posting.  You can compare our progress by looking for the two white rocks on the western wall of his photo, also seen here near the southern corner of the wall.  We have a long way to go!
The northern wall of the room has bowed inward since George Pepper excavated here—this is clear from the historic photographs of the room.  So today the stabilization crew came and put a screw jack in place—this involves putting squares of plywood against the northern and southern walls and a large pipe in between that is threaded so that they can gradually push the plywood tightly against the walls.  This will prevent the walls from falling into the room and keep the crew safe.  It won’t make our photographs look very pretty though!
Stabilization crew putting the screw jack in place in Room 28
Our hardworking crew is out at the site from 7:15 to 3:30 daily.  Five are UNM graduate students: Leigh Cominiello, James Davenport, Scott Gunn, Jacque Kocer, and Jennie Sturm.  One is starting Amherst College in the Fall: Yvonne Green.  Some of them will be posting on this blog in the coming weeks.  We’ve talked to visitors from all over the world. 

Tuesday, June 4, 2013

First Days at Pueblo Bonito

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Greetings from Chaco Canyon!  We began excavations in Room 28 at Pueblo Bonito on Monday, June 3, 2013.  The NPS wanted to keep the excavations secure by constructing a tent over the entire room.  The wonderful stabilization crew, under the supervision of Archaeologist Dabney Ford, had designed a clever way to cover the room.  By 10:00 AM, they had built a portable “garage” over the excavations.  With the addition of a few tarps and sandbags, the structure provides shade during the hot days, protection from rain, and security for the dig at night. 
After photographing the room, searching for surface artifacts, and taking depth measurements, we put our first shovel in the room at about 10:30.  The material in the room is what archaeologists call “backfill”—that is, dirt, rocks, and other material that is put in an excavation after it is finished in order to keep the space from collapsing AND to protect people and animals from falling into the excavated area.  So someone had backfilled Room 28—probably the Hyde Exploring Expedition archaeologists George Pepper and Richard Wetherill.  Our Ground Penetrating Radar analysis of the room (see poster from earlier posting) had shown some anomalies that suggested rocks and burned beams, but we really had no way to know what we would encounter in Pepper’s backdirt.
The first layer was fine sand with almost no artifacts, as the photograph shows.  But just below this layer we began to encounter charred wooden beams—large and well preserved.  While we do not know where they came from, they certainly came from Pueblo Bonito somewhere, so we are collecting the best preserved for tree-ring dating and species identification.  Pepper had noted that both Room 28 and adjacent Room 55 burned.  Since Room 55 was excavated later than Room 28, it is possible that Pepper used the dirt he excavated from Room 28 to fill in Room 28.  It is much less likely that he used the dirt from Room 28 to backfill the room.  Because the lower level of Rooms 28 and 55 were once part of a single long room, if the beams indeed came from Room 55, they might actually help date Room 28 as well.  The dates may help us figure out where the beams came from.
Other than burned beams, we are finding few artifacts in the first layers of Room 28—only an average of one piece of broken pottery in each bucket, a few scattered pieces of animal bone, and a couple of fragments of chipped stone.  We are still at least one meter (about one yard) above the surface on which Pepper found the cylinder jars in Room 28.  At our present rate, it will take about two weeks to reach that level.