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The Excavation of Monk's Mound at Cahokia

IMG_3022.JPGThere is a really interesting discussion of the August 2007 excavation of Monk's Mound at Cahokia going on on the Talk Page for the Wikipedia entry for Cahokia. I was there was a tourist when excavation began and took a lot of photos, including some of the excavation. Someone has posted the following report of the situation.

Cahokia Mounds management did not have a permit to dig into monks mound. The Illinois Historic Preservation agency gave them permission to remove only the historic fill. The site director did this on his own initiative. I saw the letters on the IAS website detailing the site management's explanation of the work on monks mound. They claimed to be doing this work to reduce the risk of erosion and to correct the slumpage issue which occurred over 20 years ago. Their comments to the Illinois Archeology Society are an indictment that they never even considered the archeology when the 30,000 cubic feet of monks mound was torn out of the mound from three separate areas. The site management explanation makes the problem apparent that they did not consider the archaeological impact that this work would have. The fact is that the mound is actually a series of ancient sacred temples stacked on top of one another that the mound may have been covered with elaborate earthen layer of colored in blue, red, white, black, grey, brown, and orange soils. The site management never mentioned the other "Rejected Possibilities" that were proposed for this work in Cahokia Archaeological Society meetings. The website also makes it clear the professional archaeological community had no idea that this work was going to be done. I served as Vice President of the Cahokia Archaeological Society for 2004-2006 and this work of digging deeply into the mound was never mentioned to the CAS. However, the site management did state in the CAS meetings they said they were looking forward to doing some "minor cosmetic work" on the mound. An elaborate earth painting or series of earth paintings covering the mound is a real possibility considering the complexity of color use in the top 10 feet of the surface of the mound. The unfortunate fact is that no floats were taken, no artifact bags lying around, or clip-boards were on site, No screening took place and the dirt was removed with track-hoe (no hand excavations going on at the time of destruction), and the dirt was piled up in multiple areas around the mound. As of August 25th, the large piles of dirt were still piled on top of monks mound but the excavations were completely filled in with loam with grass seed freshly spread on the soil that had been dumped in place by a dump truck. There was a large geotextile covering half of the newly deposited soil. After attempting to inspect the mound, I was told to stay off the mound by construction workers, who had parked their vehicles on the top of the mound. Construction and crew workers were parking vehicles on top of the smaller mounds, not to mention very large backhoes parked on the top of the mounds. According to Paula Cross, they were only supposed to remove the previous repair fill - and not impact the mound fill. But they went over a meter deep through a 50 ft wide and 50 ft long area. I calculated the volume of removed moundfill to total 30,000 cubic feet based on measurements of the piled up dirt south of the silos that are between Monks Mound and Woodhenge. The IHPA gave site directors permission to repair the damage. The depth of the excavations may have been caused by accidental removal of too much soil. However, a contractor should know that when digging into an archaeological site, the permits must be followed exactly. After a circle of limestone slabs and cedar posts had been hit by the backhoes, Tim Pauketat, an archeology professor at the University of Illinois stopped this excavation and expressed his unhappiness with the work (according to the IAS newsflash website).
The site management told me that "as long as its ripped wide open" then we should salvage what we can find. So they hired archaeologists to look at the profiles of the excavations for a few days. During this time, there were drawings made and measurements taken of the exposed features. However, "as long as it's ripped wide open" was illegal and should never have happened. Foremost for the reason that it is a desecration of sacred burial mounds.

A Doctor of Geophysics with professional licenses including geology, groundwater hydrology, and geophysics, looked at the slumpage with me after it occurred in 2004. His professional opinion of the slumping situation is to improve surface drainage of the mound by installing drainage. Possible methods include installing drainage tubing around the surface of the mound to allow for stormwater runoff to be diverted away from the mound. He said also pumped wells or drainage tubing could be installed to pump the waters out of the mound in extreme situations (like landfills). The archaeological impact of this work is the foremost consideration when deciding what to do. Basic soil engineering mechanics show that the area from the bottom of the excavation to the 45 degree angle from vertical is the affected range of soil. The unsupported excavations with backhoes in monks mound subject a much greater area to the catastrophic collapse. The excavations were about 40 feet deep vertically. The 40 feet over from the top edge of the excavations falls into the angle of repose. This means that point of unstable soil caused by slippage into the mound is now located 40 feet closer to the center of the top of the mound. The recommended methods used to reduce erosion and slumpage in saturated soil includes planting a strong cover of vegetation, and installing stormwater fences with drainage tubing. These recommendations were presented to site directors before the digging into monks mound with a backhoe occurred. Digging into the mound made the problem worse because the angle of repose was ignored. The clay soil of the mound will provide a slip zone for the loam that was deposited on the mound. Also, soil profiling was done after the cuts into the mound were made by the Backhoes. The soil from the mound was not sifted by anyone and this work was done in the area of the "birdman" tablet discovery. I walked around the piled up heaps of monks mound, and quickly found 14 sherds of bright red pottery on the surface of the heaps. Some of the pottery was vivid purple or magenta and red. Preservation is defined as following the laws to protect the archaeological sites. The limestone cairn lined with cedar logs and charred remains that was hit by the backhoe is most likely a burial. The Collected Works of Gregory Perino show many examples of limestone circles, and almost without exception, these surround burials. You might want to further consider the legal problem. Before disturbing an archaeological site a contractor is required to have a permit from the state historical preservation agency. If they only had a permit to remove the historic fill, then there was a criminal violation. The contractor had to know this and Site management had to know this. Below are the links to all the photos that I have taken available on Monks Mound during the destruction. https://i243.photobucket.com/albums/ff280/Marburg72 --Marburg72

A response to this statement has been posted HERE on a User Talk page on Wikipedia.

Monks Mound My responses to the statements listed, are below those of the complainer and should help clarify this situation. Cahokia Mounds management did not have a permit to dig into monks mound.

False Statement. There was a permit for the repair project on the mound from IHPA and the IHPA initiated the project through the Capital Development Board after two years of research, consulting, engineering and geotechnical studies. Management did not dig into the mound but after numerous meetings with the A&E, Oates & Associates, and Shively Geotechnical, Inc, the IHPA and CDB officials authorized the project and bids went out for a contractor to do the earth removal and reapairs, which went to Plocher Construction.

The Illinois Historic Preservation agency gave them permission to remove only the historic fill.

False Statement.  The contract documents state that it would be necessary to remove not only the fill that had been placed in 1988 but also the mound soil displaced by the slumping and to cut back behind the slip faces,or slickensides, in terraces into intact mound fill in order to provide stable soils on which to compact the new repair soils.

The site director did this on his own initiative. I saw the letters on the IAS website detailing the site management's explanation of the work on monks mound. They clained to be doing this work to reduce the risk of erosion and to correct the slumpage issue which occurred over 20 years ago. Their comments to the Illinois Archaeology Society are an indictment that they never even considered the archeology when the 30,000 cubic feet of monks mound was torn out of the mound from three separate areas. The site management explanation makes the problem apparent that they did not consider the archaeological impact that this work would have. An article on this project will appear in the next Cahokian quarterly, published by the Cahokia Mounds Museum Society, and the principals involved will be presenting professional papers on it at the upcoming meetings of the Illinois Archaeological Survey, the Midwest Archaeological Conferenced, and the Southeast Archaeological Conference. These should help dispel some of the misunderstandings, misinterpretations, and myths surrounding this project, such as those perpretrated by the complainer.  

Misinformation and false or incorrect interpretation of statements.  The site director did not do this on his own initiative. As state above there were numerous people involved in this decision and how to proceed. It is true that the repair of the slump was the primary factor in order to keep the slumping from eating back further into the mound. It is not correct that the archaeology was never considered. From the beginning, before remediation took place, geomorphologists and archaeologists examined cores made into the slump areas and the contract required that an archaeologist be on hand at all times during any work on the mound to observe anything that might come up and they always had the authority to stop the project if something unusual was encountered. Once the project proceeded, it became apparent that to get behind the slip faces, much more soil had to be removed than originally anticipated and that larger exposures would be created, requiring more than just monitoring the cuts and that much more archaeological documentation was needed and would be possible, which was done. Only two areas of the mound were examined, not three, and the soil was removed with amazing precision with a trackhoe in well-defined terraces.

The fact is that the mound is actually a series of ancient sacred temples stacked on top of one another that the mound may have been covered with elaborate earthen layer of colored in blue, red, white, black, grey, brown, and orange soils.

There were layers and basketloading consisting of different colors and textures--sands, silts, silty clays and clays and the layering may have been intentionally done, and some have suggested to help provide internal drainage.  One profile did show a probably former mound face with a light colored soil. Most soils ranged from light colored sand to variations of black, gray and brown. The orange was the result of oxidation of iron in some of the soils from moisture penetration.

The site management never mentioned the other "Rejected Possibilities" that were proposed for this work in Cahokia Archaeological Society meetings. The website also makes it clear the professional archaeological community had no idea that this work was going to be done. I served as Vice President of the Cahokia Archaeological Society for 2004-2006 and this work of digging deeply into the mound was never mentioned to the CAS. The possibility exists that it was done by accident. However, the site managment dis state in the CAS meetings they said they were looking forward to doing some "minor cosmetic work" on the mound.

Brief mentions of the proposed repairs were mentioned at several meetings but the final details were not worked out until more recently and it was not really necessary to discuss fine details to the group as they play no role in decision making at the site. The idea of terracing back into the mound was brought up but as mentioned, it was not until the project was actually underway that it then became necessary to go deeper into the mound than originally anticipated, and this was between meetings of CAS.

An elaborate earth painting or series of earth paintings covering the mound is a real possibility considering the complexity of color use in the top 10 feet of the surface of the mound.

There may have been selective uses of colored earth on the mound but not enough has been exposed to confirm that for sure.  And, the exposure on the north side looked very different than the east, so it does not seem there was a consistent covering, if there was one. Actually, there is less complexity of color in the top ten feet than there is in the lower portions exposed.

The unfortunate fact is that no floats were taken, no artifact bags lying around, or clip-boards were on site, No screening took place and the dirt was removed with track-hoe (no hand excavations going on at the time of destruction), and the dirt was piled up in multiple areas around the mound.

False Statements.  Archaeologists from Washington University took over one hundred soil samples from the exposures, especially at soil layer intefaces.  Surprisingly, only a handful of artifacts were found in the entire project, a few pottery sherds and chert flakes, and these were bagged when found according to their provenience.  Hand excavation was carried out for two weeks by dozens of archaeologists and students, shovel scraping and troweling the exposed terrace faces and side profiles. Numerous hours were spent mapping and documenting all these faces and over 1000 detailed digital images were made of all of them.  It is deplorable and insulting and incredibly insensitive that this complainer refused to recognize the efforts made by so many people for two weeks in 100 degree weather to say no archaeology was done. Obviously he was not there when the work was in progress or he would know better. We have numerous photos showing the work in progress. In fact, the archaeologists shut down the contractors for two full days in order to get the mapping and documenting done and get ahead of the backfilling process.  Also, the dirt piled up at the base of the mound was not the dirt removed from the slump but dirt brought in for the repair project, as was the dirt on top of the mound.

As of August 25th, the large piles of dirt were still piled on top of monks mound but the excavations were completely filled in with loam with grass seed freshly spread on the soil that had been dumped in place by a dump truck. There was a large geotextile covering half of the newly deposited soil.  

False Statements. The dirt placed in the slump was not "dumped in place by a dumptruck" which would have been obvious to anyone who actually saw what was going on. Obviously, the dirt was trucked in to the base of the mound. Then a large trackhoe lifted the soil which was NOT loam but gumbo clay selected especially for this project from a borrow bit in the region that was cleared for use. Once the soil was placed, small machines distributed it in one foot horizontal levels over a geotechnical grid placed on the terraces and between each 1 foot lift. Then a compacting machine compacted the soil which the soil engineers then tested for proper compaction. This was the process that the soil engineers said would be the most successful procedure. This was then seeded by hand with brome grass, which is a good, sturdy, drought resistant grass that we have used on other parts of the mound. Geotechnical matting was then placed over most the repair to hold down the soil and stabilize the surface while the new grass grows up through it. Once grown, the matting will not be visible and will continue to help with stabilization. The soil piles on top of the mound will be used to fill in other erosions, low spots and dips around the edges of the summit that are channeling water down gullies or ponding it on the top, contributing to some of the problems. It is also a gumbo clay

After attempting to inspect the mound, I was told to stay off the mound by construction workers, who had parked their vehicles on the top of the mound. Construction and crew workers were parking vehicles on top of the smaller mounds, not to mention very large backhoes parked on the top of the mounds.

There was no need for him to be "inspecting" the mound, especially in the areas that had already been filled.  Some of the contractors did drive to the top of the mound as that is where they needed most of their equipment. And there was a trackhoe ontop as that was needed to place the soil filling in the upper terraces and the bucket was used to help compact the soil as well.  Other vehicles were not parked on smaller mounds but parked around the base of Monks Mound under trees.

According to Paula Cross, they were only supposed to remove the previous repair fill - and not impact the mound fill. But they went over a meter deep through a 50 ft wide and 50 ft long area. I calculated the volume of removed moundfill to total 30,000 cubic feet based on measurements of the piled up dirt south of the silos that are between Monks Mound and Woodhenge. The IHPA gave site management permission to repair the damage. The depth of the excavations may have been caused by accidental removal of too much soil. However, a contractor should know that when digging into an archaeological site, the permits must be followed exactly.

   As noted before, it was always known that we would have to remove more than just the old backfill and cut into the mound fill some. It just turned out to be more than originally anticipated, but none more than was necessary. It was not accidental and the contractors did follow their contracts. I believe he misinterpreted Ms. Cross' comments.

After a circle of limestone slabs and cedar posts had been hit by the backhoes, Tim Pauketat, an archeology professor at the University of Illinois stopped this excavation and expressed his unhappiness with the work (according to the IAS newsflash website).  

Incorrect Statements.  A series of limestone slabs was hit by the trackhoe and the archaeologist in charge immediately stopped them from digging more at that location. I (site archaeologist) came up to to project immediately after that happened and also told him we would need the contractor to stop working in this area.  Tim Pauketat came up shortly after that to take some photos, saw the freshly exposed stones and asked if we had stopped the machines and we said yes. Tim did not stop the project and the IAS newsflash I saw did not state that he did. It did state that he had expressed his displeasure with the project to IHPA.  Furthermore, this was not a "circle" of slabs, but a stack of slabs of many sizes that had partially been displaced by ancient slumping and erosion, as is obvious in their tumbled and scattered placement. There were two wood remnants (at least one now identified as bald cypress) that had also been displaced by the ancient movement and knocked or compressed by overburden to be somewhat horizontal.

The site management told me that "as long as its ripped wide open" then we should salvage what we can find. So they hired archaeologists to look at the profiles of the excavations for a few days. During this time, there were drawings made and measurements taken of the exposed features. However, "as long as it's ripped wide open" was illegal and should never have happened. Foremost for the reason that it is a desecration of sacred burial mounds.    

It was not site managment but the volunteer coordinator that made that statement and in the context that he really did not know exactly what was going on and that it would be good to recover whatever information that could be while it was open.  The archaeologists had already been hired since the beginning of the project and as mentioned before, many other archaoelogists and students, including soils specialists, helped out when this became a larger project and for much more than a "few days." Some days there were 15-20 people working on documenting all the soil profiles and features.  As far as saying this "should never have happened," how ignorant. I guess the complainer would prefer to see the mound eaten away by more erosion and slumping. We did what was needed to repair and stabilize the impacted areas. It would be desecration NOT to do something.

A Doctor of Geophysics with professional licenses including geology, groundwater hydrology, and geophysics, looked at the slumpage with me after it occurred in 2004. His professional opinion of the slumping situation is to improve surface drainage of the mound by installing drainage. Possible methods include installing drainage tubing around the surface of the mound to allow for stormwater runoff to be diverted away from the mound. He said also pumped wells or drainage tubing could be installed to pump the waters out of the mound in extreme situations (like landfills). The archaeological impact of this work is the foremost consideration when deciding what to do.

Basic soil engineering mechanics show that the area from the bottom of the excavation to the 45 degree angle from vertical is the affected range of soil. The unsupported excavations with backhoes in monks mound subject a much greater area to the catastrophic collapse. The excavations were about 40 feet deep vertically. The 40 feet over from the top edge of the excavations falls into the angle of repose. This means that point of unstable soil caused by slippage into the mound is now located 40 feet closer to the center of the top of the mound. The recommended methods used to reduce erosion and slumpage in saturated soil includes planting a strong cover of vegetation, and installing stormwater fences with drainage tubing. These recommendations were presented to site directors before the digging into monks mound with a backhoe occurred.    The plan to fill in the depressed areas on the summit and edges will help to redirect and shed surface water more evenly and have a similar effect. We have tried to install drain tubes in the west slump area but they were not successful. One has to directly encounter the perched water deposits and it is almost impossible to determine those exact locations.  Some of the other ideas have been examined and rejected for various reasons. Besides, any of those plans would not repair the slump! They might help prevent future ones, but this project was to repair and stabilize the mound. The recommendations followed were presented by professional geotechnical people and  soil engineers who are more than qualified and it is insulting to imply they do not know what they are doing and that only the complainer knows what is best

Digging into the mound made the problem worse because the angle of repose was ignored. The clay soil of the mound will provide a slip zone for the loam that was deposited on the mound. Also, soil profiling was done after the cuts into the mound were made by the Backhoes. The soil from the mound was not sifted by anyone and this work was done in the area of the "birdman" tablet discovery. I walked around the piled up heaps of monks mound, and quickly found 14 sherds of bright red pottery on the surface of the heaps. Some of the pottery was vivid purple or magenta and red. Preservation is defined as following the laws to protect the archaeological sites.    

The soil of  the mound, as noted previously, is quite mixed, with sands, silts and clays. The soil of the repairs, again, was NOT LOAM, but bottomland gumbo clay. This was used because the same soil had been used for another successful repair on the north side of the mound in the early 1990s, and it held well. Laying and compacting the clay in horizontal layers with geotechnical grid, back beyond former slip faces, will have a good chance of success. Nothing is guaranteed and there may be future failures here or elsewhere on the mound and we will have to address those at that time.  The amount of soil removed was not sifted. Part of this was due to the volume involved, plus about 90% of the removed soil was old backfill or displaced soil, only about 10% intact mound fill. It was not possible for the contractors to keep the old, displaced, and new soils separated in the removal process. Plus, as mentioned before, when cleaning and preparing the soil profiles for mapping, almost no artifacts were found. This is a valid archaeological sampling procedure.  Although it would be nice to find  artifacts, our primary goal was to document the structure of the mound while exposed, and it was essential to keep the time of exposure to a minimum to avoid storm damage. We were fortunate  that it was a dry two weeks. Also, most artifacts found were not directly associated with surface activities but included in the fill used by the Indians to build the mound. The exception being the limestone slabs.

The limestone cairn lined with cedar logs and charred remains that was hit by the backhoe is most likely a burial. The Collected Works of Gregory Perino show many examples of limestone circles, and almost without exception, these surround burials. You might want to further consider the legal problem. Before disturbing an archaeological site a contractor is required to have a permit from the state historical preservation agency. If they only had a permit to remove the historic fill, then there was a criminal violation. The contractor had to know this and Site management had to know this.    

The limestone structure might be burial associated or not. We will never know for sure. Only a small portion of one end was exposed.  It was not a circular feature from what we could see. There were no charred remains associated with it, however there was a deposit or dark organic matter that was determined to be decayed wood (species not identified yet), which had been in a horizontal position. In the vertical profile, it can be seen as a dark curving band that lines up with more of the log remnant that had been exposed to the east. Apparently, as the log decayed the soil above it collapsed into the void, as can be seen in the profile. This was not a central chamber.

The complainer is not aware of all the procedures that were followed to organize and authorize this project and therefore not in a position to objectively criticize it, other than with personal biases. The laws were followed in all aspects, as were professional archaeological methods. An article on this project will appear in the next Cahokian quarterly, published by the Cahokia Mounds Museum Society, and the principals involved will be presenting professional papers on it at the upcoming meetings of the Illinois Archaeological Survey, the Midwest Archaeological Conferenced, and the Southeast Archaeological Conference. These should help dispel some of the misunderstandings, misinterpretations, and myths surrounding this project, such as thoed by the complainer.

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