Chucalissa is a Choctaw word for "abandoned house". The mounds constructed on this bluff were deserted at the time the Europeans moved into the area. It is believed that the area was occupied, abandoned, and reoccupied several times between 1000 and 1550 AD. At its height in the 14th century, Chucalissa was home to 800 to 1000 people. This lesson will focus on how the geology of this area affected the inhabitants.
Formation of a Bluff
The inhabitants of this region chose to build their mounds at the top of the bluff overlooking the Mississippi River. A bluff is a steep cliff, or wall of rock or soil. Most bluffs border a river or its flood plain. Bluffs form along a river where it meanders, or curves from side to side. Water on the outside of the curve flows faster. This erodes, or wears away, the lower part of a river bank. No longer supported, the upper part of the bank breaks off, leaving a high, steep wall. This particular bluff is composed of eroded Pleistocene loess over Pliocene glacial gravel. Loess is a geologic term that refers to deposits of silt (sediment with particles 2-64 microns in diameter) that have been laid down by wind action.
If you walk the nature trail here and proceed to stop #16, you will be very near the edge of the bluff. While the view may be partially obscured by foliage during summer months, you can clearly see the difference in elevation from top to the flood plain below.
Formation of a Flood Plain
The people who constructed these mounds used the rich fertile soils of the flood plain located at the base of the bluff to grow a variety of crops. A flood plain is a flat or nearly flat land adjacent a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge. Floodplains can support particularly rich ecosystems, both in quantity and diversity. This made the area particularly good for agriculture. The diorama inside the museum will provide you with a good idea of how the bluff and flood plain made for an ideal environment for the inhabitants.
How did humans affect the landscape?
Constructed in stages from around 1310-1500 AD, the larger platform mound was constructed from loads of dirt carried from a "borrow pit". This term describes an area where material (usually soil, gravel or sand) has been dug for use at another location. This mound measures over 150 feet across at the base, and about 100 feet long at the top and 25 feet tall. A mound of these dimensions would have taken over 350,000 basket loads of material to build.
How has erosion affected the area?
The smaller mound predates the larger platform mound by 100 years. Archaeologists have determined that it was, at one time, a platform mound as well. The mound was subjected to farmer's plowing and the natural forces of erosion. Erosion is the process by which soil and rock are removed from the Earth's surface by natural processes such as wind or water flow.
Requirements for logging this cache:
1. What is your elevation at the bluff?
2. What physical characteristics of the bluff made it an ideal place for the inhabitants to reside?
3. Proceed to the additional coordinates for this listing. This will take you to a marker located on top of the large mound. There is a geologic term on this sign in RED letters. What is the definition of this term, and how does it relate to this area?
4. Compare the large and the small mound in the plaza on top of the bluff. It is believed they were once similar in size. Estimate how much wind/water erosion has affected the smaller mound. (compare the size of the mounds)
5. (Optional) Please take a photo of yourself and/or your group during your visit to the EarthCache. While photos are no longer required to log an EarthCache, they are encouraged.
Email these answers to the cache owner by clicking the username at the top of the page.
Chucalissa Museum charges a small admission fee for maintenance and upkeep of the facilities. The fee schedule is as follows:
Children Under 4 free
Ages 4-11.........................................$3
Ages 12-59.......................................$5
Seniors.............................................$3
Groups of 10 or more....................Adults $4 and Children $2
Monday.................................Closed
Tuesday.................................9:00 a.m. - 5:00 p.m.
Wednesday............................9:00 a.m. - 5:00 p.m.
Thursday................................9:00 a.m. - 5:00 p.m.
Friday.....................................9:00 a.m. - 5:00 p.m.
Saturday................................9:00 a.m. - 5:00 p.m.
Sunday..................................1:00 p.m. - 5:00 p.m.
*Last admission will be one half hour before closing time.
**Closed most major holidays.
This EarthCache was developed with permission from the director of the C.H. Nash Museum at Chucalissa.