This earthcache is placed with permission from Mounds State Park. There is an admission fee to the state park.
Getting Started
Our sandy dunes, flat prairie land and rolling hills that make up the landscape in Indiana were all created by a thick sheet of ice.
Glaciers are massive bodies of ice that slowly move across the landscape. They form by layers of snow compacted over the years to form a very thick layer of ice. Two primary types of glaciers exist: continental and alpine. Continental glaciers are large, dome-shaped sheets of ice and are vastly spread throughout the land. Alpine glaciers are found in mountain regions and in their valleys.
Under the pressure of its own weight and by the force of gravity, glaciers will flow outwards and downwards like a giant frozen river. These massive pieces of ice have a profound effect on the lay of the land as it moves the earth, breaks down rocks and creates hills. Our own landscape was transformed drastically during the last Ice Age. Without this natural phenomenon, Indiana wouldn’t be as unique as it is today.
How Glaciers Shaped Indiana
Around 16,000 years ago glaciers covered Indiana. Parts of the glaciers were known to be up to a mile thick! For hundreds of years, the glaciers, commonly known as the Wisconsin Lobe, moved about a foot a day. While moving outward and then retreating back, the glaciers carved the land. As the ice melted, the glaciers created and left behind dunes, hills, rivers and lakes. Some of the erratics left behind were from as far away as Canada.
There are basically two types of landscape present in Indiana. In the northern and central parts of the state, the land is flat plains. In the southern region, the landscape is hilly with great stands of forests. It was during the last ice age where these stark differences developed.
Glacial ice extended and retreated several times in the Midwest during the Pleistocene epoch, or the Great Ice Age. Yet every glacier that spread over Indiana never extended past the central region of the state. Once the glaciers melted the dirt, rocks and sand - or glacial till - that were picked up by the ice were all that was left behind. Any hills or valleys created by previous ice ages were filled with this till and left the land flat. Today this central area is known as Tipton Plain Till. In the northern part of the state, where glaciers retreated more quickly, moraines - or glacial till ridges - were left, but was still left relatively level.
The result of the glacial activity in the area made it possible to have humans construct these mounds. The glacier would scrape off the earth and deposit gravel, known as till, to the area over the existing bedrock. The till is used in construction purposes from the Indian mounds in this park and to gravel pits in central Indiana as well. If there was not till remnants in this area, they could not have built the mounds.
Erosion of the mounds
Many of the region’s mounds were destroyed when land was cleared and plowed for agriculture. The fact that the park’s mounds exist is a credit to the Bronnenburg family. These original property owners refused to plow the mounds and protected them from looters. Even so, the mounds have management concerns:
a. Natural erosion is wearing down the embankments and filling in the ditches. Archaeologists estimate that the original ditches on some mounds may have been three to six feet deeper than present.
b. Human-caused erosion has escalated the problem. With the exception of the Great Mound, the mounds are unprotected from foot traffic. A horse trail once crossed the Great Mound. During the amusement park days, people would drive Model T Fords around the top of the Great Mound.
c. Trees. The area around the mounds was treeless when the Adena were using them. They required a clear horizon line, free of obstacles. Today, the mounds are dotted with large trees. While this gives a park-like appearance, the trees greatly endanger the integrity of the mounds. Eventually, the trees will fall, pulling up their root balls. This will significantly destroy the mound’s archaeological potential.
How it was made
Anderson Mounds, part of Mounds State Park and, located near Anderson, Indiana, is a burial site that developed out of the Hopewell culture. These earthworks were created as a dedication to the Sun God and Earth Mother, and the mounds were used as gathering places for religious ceremonies as well as viewing astronomical alignments. The Great Mound is the largest of the ten earthworks in the Mounds State Park, and its construction dates back between 250 and 160 B.C. The three floors of the Great Mound were created by a repeated process that included adding a layer of subsoil, which was clay, burning the ground, then covering the floor in a layer of powdered white calcite, made from bone, shell, and limestone. This gave the floor a clay consistency as well as deep purple color. Each floor had basins and pits of unknown purposes, however near the gateway of the mound platform, a large pit was found containing various artifacts. These artifacts included chipped stone, flakes, burned bone, a fragment of shell, fragments of mica, and burned clay chunks. Built above this pit was a log tomb, called so because the floor of the tomb was laid with logs. When excavated, two human burials were found inside the tomb; a 50-year-old adult male, and the redeposited partial remains of a cremated individual. Also, artifacts such as a limestone platform pipe, flakes, fire-cracked rocks, mica fragments, pottery, burned and unburned bone, and seven deer bone awls were found in the tomb. 100 years after the mound was started, the construction of the Great Mound's platform was started. Although the embankment appears random and irregular, it was actually carefully crafted. The only other aboriginal features on the platform were numerous small post holes encircling the top. These holes most likely held a brush fence erected to hide activities carried out on the platform. After the mound was completed, several more pits were dug, some of them spanning from the surface to the lowest floor. One pit was possibly looted, while two other pits contained human burials.
THE INFORMATION BELOW IS ADDITIONAL AND IS NOT PART OF THE EARTHCACHE.
History of the mounds
Don Cochran, a Ball State University archaeologist, believes was used as an observatory. Dips in the earthen walls surrounding the largest mound’s central platform helped observers track the movement of the sun and bright stars. The west side of the Great Mound features alignments that follow the setting of the sun on the days of winter and summer solstice, which are the shortest and longest days of the year. It also tracks sunset on the equinox, when the hours of daylight and darkness are virtually equal.
Like many discoveries, the breakthrough at Mounds State Park was an accident. It began in June 1988 as an attempt by Cochran & a group of Ball State archaeology students to update the only existing map of the mounds. The last map that was made was back in 1870, or thereabouts, and it had some things out of place.
Cochran used a survey transit to help confirm his discovery at Mound State Park. The survey tool helped confirm the alignment of smaller companion mounds with the dips in the earthen wall surrounding the park’s Great Mound. His discovery was made on December 21, 1988 - winter solstice, the shortest day of the year. Cochran believed that if he was right with his computations and if they worked out in real life, the implications could be staggering. Just after 5:00 p.m. the big moment of truth was almost at hand, but something didn’t look right. The sun was sinking on a track that would take it too far to the left to line up with a flag marker. It seemed it was going to miss the slot in the Great Mound, but, as the sun slipped closer to the horizon alignment began to drift slightly back to the right. Cochran watched as the sun swung into line with the embankment dip. At 5:23 p.m., it sank into darkness. His theory was on target. These modest heaps of dirt were not only burial mounds or amphitheaters, as archaeologists had thought for decades, they were sophisticated observatories shaped from the earth by prehistoric humans.
For more than 2,000 years the mounds had been silently keeping track of the heavens spinning above central Indiana while no one had suspected, until that short winter day in 1988. The smaller earthworks had aligned with dips in the Great Mound’s embankment and probably helped their creators sight the sun and stars. Fiddleback mound, for instance, is on a line with the summer solstice sunset, the circular mound is aligned with the winter solstice sunset, and the shallow earthwork tracks the rise of a bright star known as Fomalhaut.
Cochran has since plotted the locations of four other ancient mound groups built around the same time. There is one near each New Castle, Richmond, Cambridge City and Winchester. Cochran has sketched in lines connecting the sites and the result is a pattern that eerily resembles the Big Dipper. And, although he has stopped short of suggesting the mounds were located in an attempt to recreate the constellation, he does marvel at the resemblance.
The tribes who built the mounds are known as the Adena and later the Hopewell, who were prehistoric Indians who lived in Indiana centuries before such better known historical tribes as the Miami and Delaware. Much of their sophisticated culture is shrouded in mystery, lost forever in time. There are no written records, and the clues they left behind are scant: shards of pottery, bits of jewelry, assorted stone tools. Very little is really known about the Indians of that time and adding to the mystery is the absence of anything archaeologists can identify as the remains of a village near the Anderson Mounds.
Information from the Indiana Historical Society on the Great Mound indicates that on the platform surrounding the earth mound were numbers of small post molds. This suggests that an irregular brush screen had guarded the activities occurring in the central region or that saplings had been bent over and tied to the heavy support posts located near the center to form a roofed shelter. Artifacts recovered, though few in number, included plain and distinctively incised pottery, mica, a plain platform pipe, and bear effigies (crude sculptures), which were drilled and carved from bone.
Questions that still puzzle historians are: Just where did the Adena leave off and the Hopewell begin? and, What was their relationship to each other? Most estimates date the Adena from 1,000 B.C. to about 100 B.C., with Hopewell flourishing from 100 B.C. to 400 A.D. Current theory is that the Anderson earth-works were built by the Adena from 1,000 B.C. to about 100 B.C. and they were later used by the Hopewell.
The Great Mound was probably first recognized by non-Indians before 1803 when land reports were sent to General Arthur St. Clair, governor of the Northwest Territory. Frederick Bronnenberg first purchased the land in 1821 & then protected the mounds until his death in 1853. His house still stands within the park grounds. The park's property remained in the Bronnenberg family until 1879. Shortly thereafter it was owned by the Union Traction Company and eventually developed into an amusement park. A carousel was operated atop the panduriform “Fiddleback” mound. Much alteration and destruction of mound surfaces occurred at this time due to amusement park activity, and in some areas, cultivation. Thankfully, visitors are no longer allowed to walk on the mounds.
The first reported excavation of the mounds was a few years before 1874 & some people believe it may have even began while Frederick Bronnenberg was still living. The target of these operations was the Great Mound. Years later, on May 5, 1931 the renowned archaeologist of the day, Warren K. Moorehead with Glenn A. Black visited the park and made a number of auger borings of various earthworks including the Great Mound. Many more years later, Indiana University, under permit and financial support of the Department of Natural Resources, extensively excavated the Great Mound during the summer of 1968 and 1969. It was then that a small secondary mound situated on the central platform surface of a large primary mound was revealed.
Indiana University’s excavation revealed the most artifacts in the Great Mound. They discovered burials, log tombs, crematory basins, garbage pits, numerous postholes, and some pottery. The pottery is decorated in zones, with thin incised lines, often forming up to five nested diamond designs. This design is similar to an excavation of Ball State University at New Castle twenty miles to the southeast. This New Castle site is dated around the beginning of the Christian Era. Since Middle Woodland Hopewell pottery has also been recovered from New Castle it is reasonable to assume that the mound complex at Mounds State Park is also Hopewell.