Exploring Agricultural Lands and Crop Failure around Mississippian Period Sites in Middle Tennessee

30 Days of Tennessee Archaeology 2015, Day 25

Andrew Gillreath-Brown
University of North Texas

Digital Elevation Model (DEM) of two subbasins - the Harpeth and the Lower-Cumberland – in Middle Tennessee with three archaeological sites – Mound Bottom, White’s Creek, and Kellytown. Map created by Andrew Gillreath-Brown.

Digital Elevation Model (DEM) of the Harpeth and the Lower-Cumberland subbasins in Middle Tennessee with three archaeological sites – Mound Bottom, White’s Creek, and Kellytown. Map created by Andrew Gillreath-Brown.

The Mississippian Period has long been seen as a time of extreme and rapid change, from intensive agriculture to the growth of large population centers and then ultimately to the collapse of the Mississippian polities in the Southeast. The collapse around AD 1500 to AD 1700 represents a complex synergy of causal processes, such as environmental degradation, conflict, drought induced water and food resource stress, and of course European contact. People react to environmental change in many different ways. These reactions do not happen on a global scale, but rather on a level where people are living their daily lives.

To examine these decisions requires a closer look at the changes in agriculture over time, especially as related to drought. One way to do this is to determine the amount of moisture that was available to crops, then determine whether crops may have failed within a given year, or at least to what degree they may have failed. Examining locations of agricultural lands near villages and the amount of potentially productive land can provide valuable information on the local environment and to the Mississippian people’s subsistence. Studying soil moisture and crop failure can complement the field of paleoethnobotany, which we saw on Day 11. My ongoing research focuses on several major sites around Nashville in two watershed subbasins – the Harpeth and the Lower-Cumberland. However, for today, I want to focus on the Mississipppian site of Mound Bottom, located just to the west of Nashville and by the Harpeth River.

Aerial photo of Mound Bottom from 1972 (image courtesy of the Tennessee Division of Archaeology)

Aerial photo of Mound Bottom from 1972 (image courtesy of the Tennessee Division of Archaeology)

The amount of crops that fail within a year can a have tremendous impact on a village’s decisions of whether to stay or migrate elsewhere, or in further developing and refining food storage/preservation techniques or trade decisions. Some scholars have examined changes in climate and crop production during the Mississippian time period (see Anderson 1996, 2001). The changes in crop production seem to coincide with large societal shifts, such as with shifts to larger aggregated and fortified villages.

An example of precipitation variability in the Southeast (i.e., North Carolina, South Carolina, and Georgia) that was derived from tree-ring data, showing the mean with the dotted line and the shaded area showing the standard deviation (Stahle and Cleveland 1992; see additional information below).

An example of precipitation variability in the Southeast (i.e., North Carolina, South Carolina, and Georgia) that was derived from tree-ring data, showing the mean with the dotted line and the shaded area showing the standard deviation (Stahle and Cleveland 1992; see additional information below).

During the Mississippian period, there was significant annual and intra-annual variability in precipitation, which may have had a major impact on agricultural productivity (Aharon et al. 2012; Anderson 1996, 2001; Anderson et al. 1995; Stahle and Cleveland 1992). If precipitation is significantly high, soil can become saturated; if significantly low, crops will reach wilting point. Both scenarios result in crop failure. Using hydrological modeling, or examining the science behind water available to crops, we examine changes in the spatial and temporal distribution of soil moisture around sites to evaluate the impact of fluctuating precipitation amounts on agricultural potential. To assess the impacts of climate on food resources, I am evaluating water conditions across the landscape to identify areas that were not suitable for crops during drought conditions, and therefore would have impacted food production. Soil moisture is the amount of water present within a defined space, like a soil column. It is essentially the inputs, like precipitation, minus the outputs, like evaporation, or water running off the surface.

The angles (degrees) of hillslopes in the area of Mound Bottom. Map created by Andrew Gillreath-Brown.

The angles (degrees) of hillslopes in the area of Mound Bottom. Map created by Andrew Gillreath-Brown.

To determine moisture conditions that may have been available to crops, we take into account four different variables including soils, topography, vegetation, and climate (annual precipitation and temperature). To determine annual precipitation and temperature, we use data from tree-rings that was collected and analyzed by dendrochronologists, or someone who studies tree-rings. By focusing on crop failure, we will be able to tell whether declines in agricultural productivity were due to a loss of plants or a decrease in the overall production of individual maize stalks. This allows us to determine whether certain areas within a watershed, surrounding major human population centers, were more or less susceptible to crop failure and how that relates to population movements. Let’s look at the area surrounding Mound Bottom.

Northern and southern aspects shown with aerial imagery. Map created by Andrew Gillreath-Brown.

Northern and southern aspects surrounding Mound Bottom shown with aerial imagery. Map created by Andrew Gillreath-Brown.

Soils can affect these inputs and outputs because differing size sediments affect how long water remains in a particular place. For example, in a sandy soil, water will quickly drain, thus it is not available very long for crops. In addition, we must also consider slope and topography. The angle of a slope can also highly affect outputs, since a steeper slope would cause water to move more quickly downhill, thus, a flat area would be better for soil moisture. Aspect – or the direction that a slope faces – can also affect evaporation and transpiration, thus moisture retention. Solar radiation is more intense with a southern facing slope, thus less moisture is retained. In the figure to the left, you can see the places that will have the most evaporation in red, thus less moisture. If you have a really dry year or several dry years, then the red areas are not going to be very good for having water available to crops. However, if you have a really wet year or several wet years, then the blue areas may end up having too much water for crops.

One drought period recorded by Meeks and Anderson (2013) occurred around AD 1288 to AD 1308. Before this period, the Middle Cumberland area had a period of large mound building – including Mound Bottom – in addition to many scattered smaller villages. However, around the AD 1250s, settlements shifted from smaller spread out villages, to larger aggregated villages with larger and more intensive fortifications. People began abandoning the lower and central portions of the Harpeth subbasin, and moved to the south to places such as Fewkes Site in Williamson County.

This project is in its early stages but it will be able to reveal new insights into the impacts of drought on the prehistoric peoples’ farmlands, and whether it was a major contributing factor to societal shifts in the Mississippian society of Middle Tennessee.


References Cited

Aharon, Paul, David Aldridge, and John Hellstrom. 2012. Rainfall Variability and the Rise and Collapse of the Mississippian Chiefdoms: Evidence from a DeSoto Caverns Stalagmite. Climates, Landscapes, and Civilizations 198:35-42.

Anderson, David G. 1996. Chiefly Cycling and Large-Scale Abandonments as Viewed from the Savannah River Basin. In Political Structure and Change in the Prehistoric Southeastern United States, edited by John F. Scarry, pp. 150-191. University of Florida Press, Florida.

Anderson, David G. 2001. Climate and Culture Change in Prehistoric and Early Historic Eastern North America. Archaeology of Eastern North America 29:143-186.

Anderson, David G., David W. Stahle, and Malcolm K. Cleaveland. 1995. Paleoclimate and the Potential Food Reserves of Mississippian Societies: A Case Study from the Savannah River Valley. American Antiquity 60(2):258-286.

Meeks, Scott C., and David G. Anderson. 2013. Drought, Subsistence Stress, and Population Dynamics. In Soils, Climate and Society: Archaeological Investigations in Ancient America, eds. John D. Wingard, and Sue E. Hayes, pp. 61-83. University Press of Colorado, Boulder, Colorado.

David W. Stahle and Malcolm K. Cleaveland. 1992. Reconstruction and Analysis of Spring Rainfall over the Southeastern U.S. for the Past 1000 Years. Bulletin of the American Meteorological Society, 73(12), 1947-1961. doi: 10.1175/1520-0477(1992)073<1947:RAAOSR>2.0.CO;2. Available at: https://www.ncdc.noaa.gov/cdo/f?p=519:1:0::::P1_STUDY_ID:16458. Accessed on August 31, 2015.

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Slipping Through the Crevices at Mound Bottom

Tracy Brown over at Archaeology in Tennessee posts a fantastic reminiscence about Mound Bottom and Mace Bluff, along with some thoughts on the site layout and symbolism.

Archaeology in Tennessee

This is another one of my folksy but true stories about good old times in Tennessee archaeology. It involves a trip I made to Mound Bottom in 1973. Mound Bottom is a large Mississippian Period site located on the Harpeth River in Cheatham County, Tennessee. It is now preserved within Harpeth River State Park. If you need some detailed background information on this site, you can read about it here: http://capone.mtsu.edu/kesmith/TNARCH/MoundBottom.html and here: http://www.nativehistoryassociation.org/moundbottom.php.

I was an undergraduate geology student at Austin Peay State University in 1973. One of my best friends, who lived on my floor in the Ellington Hall dormitory, was Paul Pitt. At that time Paul’s older brother and sister were graduate students on campus, and he introduced me to them. The Pitt family home was in Ashland City, Cheatham County, Tennessee. One of the many things I respected about the Pitt family was their deep interest…

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30 Days of Tennessee Archaeology, Day 14

The 2014 Tennessee Archaeology Awareness Month Poster!

Tanya M. Peres, PhD, RPA
President, Tennessee Council for Professional Archaeology
Director, Rutherford County Archaeology Research Program
www.mtsurcarp.wordpress.com

We are so excited to unveil the 2014 Tennessee Archaeology Awareness Month poster!

The first TAAW poster (1996; Designed and printed by MTSU Publications and Graphics and Ambrose Printing Co.)

The first TAAW poster (1996; Designed and printed by MTSU Publications and Graphics and Ambrose Printing Co.)

The first Tennessee Archaeology Awareness (TAA) poster was created in 1996 by Dr. Kevin Smith of Middle Tennessee State University. That poster was created to commemorate the first official TAA Week and featured a map of Tennessee on which numerous archaeological sites and finds were highlighted. The poster was submitted to the Archaeology Week/Month Poster contest held annually by the Society for American Archaeology, and was chosen as the FIRST PLACE winner at the SAA conference in the spring of 1997!

Posters were created for a number of subsequent years, often funded by the Tennessee Historical Commission and Middle Tennessee State University; however, Tennessee has not had an Archaeology Awareness poster in several years. This year, the Tennessee Council for Professional Archaeology is happy to revive the poster tradition with several notable changes:

  • We are celebrating an entire MONTH of Tennessee Archaeology this year! There are so many great events taking place, they could not all fit into one week. Since TAA Week fell in September, and because many Tennessee schoolchildren are learning about the prehistory of Tennessee this month as part of the new statewide Social Studies standards, TCPA Board members decided to keep September as the month to celebrate Tennessee Archaeology.
  • The poster was designed by Noel Lorson, Associate Professor of Graphic Design at MTSU. We worked together on conceptual ideas, and Aaron Deter-Wolf and I took Noel to see the Mound Bottom and Mace Bluff sites first hand. The idea was to give the poster a fresh, modern, artsy feel, while compelling viewers to learn more about Tennessee’s amazing archaeological sources and cultural history. This year’s poster does all of that and more.
  • In addition to the posters, which will be distributed to the public free of charge, we created postcards that can be used in a more traditional way (i.e., mailed to a friend or family member) or displayed as a piece of art in one’s home or office.
  • We are grateful for the Tennessee Historical Commission’s generous funding of this project. Steve Rogers at the THC and the staff of the Office of Research Services at MTSU worked to insure we would have the TAAM poster in time for this year’s celebrations.

We are so excited to share the 2014 Tennessee Archaeology Awareness Month poster featuring Mace Bluff & Mound Bottom!

2014_taam_poster

The 2014 Tennessee Archaeology Awareness Month 2014 poster. Design by Noel Lorsen.

Mace Bluff and Mound Bottom are both within the Harpeth River State Park. These two sites are geographically and temporally intertwined, and represent different ways Native Americans who lived during the Mississippian Period (AD 1000-1450) in Middle Tennessee left their mark on the landscape. The background image on the poster is a topographic map of Mound Bottom from the 1974-1975 investigations by the Tennessee Division of Archaeology, showing the elevations and placement of the mounds. Mound A, the largest and most prominent of the mounds, is located to the lower left of the poster. The central image of the mace is based on a the petroglyph at Mace Bluff, a rock art site along the bluff line overlooking the Harpeth River and Mound Bottom.

Historical marker for Mace Bluff along the trail to the site.

Historical marker for Mace Bluff along the trail to the site.

The image incised on Mace Bluff is of an artifact known as mace, or scepter, that served as symbol of authority, leadership, and ideological belief during the Mississippian period. Maces appear in Mississippian art from throughout the Southeastern US and greater Mississippian sphere, where they are typically associated with the supernatural character known as Morning Star or the Birdman.  Examples of the mace appear on a marine shell gorget from the Castalian Springs site in Sumner County, Tennessee, the copper Rogan Plate from Etowah, Georgia, and on rock art in Missouri and Tennessee. A number of complete stone maces have been recovered from Tennessee, as well as from sites like Spiro Mounds in Oklahoma.

The Mace Bluff petroglyph. The mace is considered to be a symbol of authority and restricted to ceremonial uses.

The Mace Bluff petroglyph. The mace is considered to be a symbol of authority and restricted to ceremonial uses.

The view of Mound Bottom from Mace Bluff allows one the opportunity to reflect on the people that built this town and ceremonial center approximately 1,000 years ago. You can read about the history of investigations and interest in Mound Bottom, as well as a summary of what is known about its archaeological components in yesterday’s blog post by Aaron Deter-Wolf.

View from Mace Bluff of the Mound Bottom site across the Harpeth River.

View from Mace Bluff of the Mound Bottom site across the Harpeth River.

The grass covered earthen mounds at Mound Bottom are a testament to the builders’ architectural ingenuity, the location highlights their concern with access to transportation and trade routes, and the layout gives us insight into their sense of urban planning. The petroglyph at Mace Bluff ties into these themes, and shows a dedication to their spiritual beliefs and heritage.

To find out where you can get a Tennessee Archaeology Awareness Month poster or postcard, email us at Tennessee.Archaeology@gmail.com, or use the contact form below. Please include your full address when you contact us, and note that quantities are limited.

30 Days of Tennessee Archaeology, Day 13

A Visit to Mound Bottom

Aaron Deter-Wolf
Tennessee Division of Archaeology

Mound Bottom State Archaeological Area is located along the Harpeth River in Cheatham County, and includes one of the largest Mississippian period archaeological sites in Middle Tennessee. The main site area was purchased by the State of Tennessee in 1973, and in 2005 became part of the Harpeth River State Park. In 2008 an adjacent 65-acre parcel including additional site area was purchased with the assistance of Tennessee Parks and Greenways Foundation.

1923 map of Mound Bottom by Crawford C. Anderson

1923 map of Mound Bottom by Crawford C. Anderson

Since the late 19th century Mound Bottom has been the subject of limited archaeological investigations including those by the Peabody Museum at Harvard (1878; link opens a large report PDF), William E. Myers (1923), Tennessee’s first State Archaeologist Parmenio E. Cox (1926), and the University of Tennessee (1936-1937). The only modern excavations at the site were conducted in 1974-1975 by the Tennessee Division of Archaeology and published in 2012 in the journal Southeastern Archaeology.

View of Mound A from the site entrance, facing east towards the main plaza.

View of Mound A from the site entrance, facing east towards the main plaza.

When you visit Mound Bottom today you approach the main plaza from the west and are presented with a view of the rear face of Mound A, the largest of the 14 mounds at the site. Mound A measures about 246 feet on each side, and originally stood more than 36 feet tall (in an 1878 map the height is identified as 45 feet). Test excavations by the Tennessee Division of Archaeology in 1974 and 1975 determined that following initial construction Mound A was enlarged in at least three stages, first around AD 976 and again around AD 1147. The upper surface of the mound originally held one or more buildings, which would have functioned as ritual spaces and/or residences of individuals with elevated social status.

When the site was occupied, Mound A would have been accessed by a central stairway located at the middle of its eastern face. In late 19th or early 20th century a new access ramp was cut into the north face of the mound, and according to oral histories, the summit was cultivated as a watermelon patch around this time. The uppermost mound stage was heavily disturbed by historic plowing, and as a result the time frame for the final construction phase and layout of structures on the summit remains unknown.

View of Mound A in 1926. Image courtesy the P.E. Cox papers, Tennessee State Library and Archives

View of Mound A in 1926, planted in corn. Image courtesy the P.E. Cox papers, Tennessee State Library and Archives.

The main plaza at Mound Bottom encompasses 6.5-acres to the east of Mound A and is bounded by a total of ten smaller mounds. A single mound known as Mound L is situated along the eastern edge of the plaza. Many of these mounds exhibit multiple construction stages indicating they too were improved and expanded throughout the history of the site. Today the mounds surrounding the plaza appear rounded on their summits. However, excavations have revealed that almost all of the small mounds at the site were originally flat-topped platforms.

Today when we visit Mississippian mound sites we see grass-covered, empty spaces. However, in their heyday there was likely little grass to be found in these thriving centers. Plazas consisted of hard-packed earth, while the mounds themselves would have been covered in clay or in some cases colored earth. The areas outside of the plazas were typically filled with wattle and daub houses and distinct cemetery areas. Other important non-mound structures were sometimes situated within the plazas. The floodplain of the Harpeth River surrounding Mound Bottom would have been thickly planted with fields of corn, the main staple of the Mississippian diet.

Excavated house footprints west of Mound A, dated to dated to about AD 976. Image courtesy the Tennessee Division of Archaeology.

Excavated house footprints west of Mound A, dated to about AD 976. Image courtesy the Tennessee Division of Archaeology.

A large wooden palisade may have surrounded the Mound Bottom site area between the mounds and the river. While the presence of this feature remains unconfirmed by modern archaeology, its presence was attested to in 19th century by Judge John Haywood, who wrote: “All around the bend, except at the place of entrance, is a wall on the margin of the river. […] On the north side of the bend and wall, is a gateway, and also on the south. On parts of this wall, at the distance of about 40 yards apart, are projected banks, like redoubts on which persons might have stood.” He further describes visible traces of a road that passed through the gateways and connected Mound Bottom to the Pack Site, another multi-mound Mississippian center located to the south on private property. No modern excavations have been conducted at the Pack Site, and the precise relationship between the two mound groups is not understood at this time.

View of Mound Bottom from Mace Bluff.

View of Mound Bottom from Mace Bluff.

Major occupation at Mound Bottom appears to have ended by around AD 1300-1350, corresponding with a period when numerous smaller Mississippian chiefdoms began to spread throughout the Nashville Basin. While there is still some evidence of occupation at Mound Bottom around that time (several house footprints have been dated to about AD 1350), it is believed that major moundbuilding activity at the site ceased during the late 13th century.

In addition to the Pack Site, Mound Bottom is also associated with several pieces of rock art located along the same stretch of the Harpeth River. The most famous of these is Mace Bluff, which features a petroglyph incised into a stone outcrop and provides a fantastic view of Mound Bottom. You can learn more about Mace Bluff – and see the 2014 Tennessee Archaeology Awareness Month poster! – in tomorrow’s post for 30 Days of Tennessee Archaeology by Dr. Tanya Peres.

Due to its sensitive nature and lack of facilities, access to Mound Bottom is by appointment only, and can be arranged through the Harpeth River State Park. The Tennessee Division of Archaeology gives periodic tours of the site throughout the year, which are announced on the Tennessee State Parks Facebook feed.