PIERRE, S.D. (AP) — They are mystery stories, written large as life in mineral ink on the pages of the Northern Plains.
A 360-foot snake — reportedly once with a blazing red tongue — slithering along a grassy slope. A long-tailed turtle lying next to a woman near an earthen mound. A large grid spread across the spur of a hill. All created from lines of small boulders.
Hundreds of these stone effigies or alignments, ranging from animal forms to mosaics, can be found across the seven Midwestern states and parts of Canada, including more than a hundred such figures in South Dakota. The mystery surrounding them has cast archaeologists, anthropologists and ethnographers as detectives trying to answer the five basic questions of any good whodunit.
Linea Sundstrom, an archaeologist with the University of Wisconsin, prepared a report on stone figures for the South Dakota State Historical Society in 2006. She catalogued 128 effigy and stone alignments across the state, including all that have been reported in the past, even if their current location and status are unknown. That does not include the dozens of stone arrangements that are tipi rings, historic foundations of buildings, cairns or mounds.
Those effigies often take on recognizable shapes: snakes, turtles, birds, fish, horses, rabbits, and humans. Then there a handful of medicine wheels — alignments with spoke-like lines radiating from a central point — and geometric forms whose meanings are no longer apparent.
Ian Brace, the former curator of archaeology and aboriginal studies at the Royal Saskatchewan Museum in Regina, Canada, did his master's thesis on the stone effigies of Saskatchewan. In his estimation there are between 500 and 600 effigies spread throughout the northern Great Plains. It's possible those effigies represent only a fraction of what existed before many were destroyed to make way for modern agriculture, he said.
Brace said the figures are spread across the short-grass Northern Plains, from central Nebraska up into Saskatchewan and from the Rockies into Minnesota and parts of Iowa, with some in Ontario and Ohio.
Among the effigies, turtles are common. There are half a dozen in Canada and Brace said the most southern effigy he knows of was a turtle figure in central Nebraska. South Dakota is home to 12 turtle forms, mostly in the central Missouri River region, but with some in the northwestern and eastern fringes of the state.
Two of three recorded thunderbird effigies are found in central South Dakota, according to Sundstrom.
The snake effigies in South Dakota are six of only seven known in the Northern Plains. Five of them — including one at Medicine Knoll near Blunt — are along the Missouri River between Okobojo Creek and Big Bend. The sixth effigy is along the James River while the last is in North Dakota near the town of Independence.
According to Sundstrom, human figures are rare in South Dakota, but occur much more frequently in Montana, North Dakota and Canada. The most prominent example of human figures in the state was probably Punished Woman Butte in Codington County, which was destroyed by 1914. The site had two figures outlined in stone, a man and a woman, depicted as lying on the ground with outstretched arms.
The question of when these effigies were built is where the real detective work begins for archaeologists. The constructions are old, but answering exactly how old is nearly impossible, the Capital Journal reported (http://bit.ly/1pQJsZh ).
Adrien Hannus, a professor of anthropology at Augustana College, said ultimately the problem with determining an age for the figures is there is nothing to date. Radiocarbon dating only works with organic matter, so that method is useless without fire pits or other signs of human activity nearby.
Sometimes studying petroglyphs — or rock engravings — that have similar designs and are often accompanied by fire pits can yield clues, he said.
An indicator of age may be the how much dirt has built up around the individual stones. However, Sundstrom said local erosion and buildup factors, plus climatic events such as the Dust Bowl in the 1930s, makes soil deposition an unreliable indicator.
Brace attempted to date figures using the lichens growing on the stones, but the method ran into numerous problems. Sulfuric gas from oil drilling or high amounts of carbon monoxide and carbon dioxide killed lichens for miles around. Getting a baseline for growth was also problematic if there was no cemetery nearby with undisturbed lichen-covered headstones.
Based on what little evidence there is, the earliest alignments were probably made 2,000 years ago, Brace said.
That agrees with the opinion of South Dakota Assistant State Archaeologist Michael Fosha, who said he believes the effigies were made in the last 2,000 years and he's even more confident that they are from the last 500 years. Many probably date from the 1700s, before European colonization of the plains, he said.
Because dating the effigies is nearly impossible, answering the question of who was around to build them is an equally perplexing task. The list of suspects is long and a combination of any of them could be responsible.
Brace said the question of who depends a lot on when a particular group was in a particular area. The Blackfoot, Cheyenne, Arapaho, Cree, and other Siouan peoples all moved across the Plains. Some of the alignments could be the work of a civilization that preceded all of them, he said.
He has visited effigy sites with different Canadian tribes, only to find the figures are not part of their oral traditions.
"Some of the features I can loosely attribute to one tribe or another, but I can't assign all of them to any one particular tribe or some to one tribe or some to another," Brace said.
Fosha said in his opinion the Cheyenne are a good contender because they crossed the Minnesota River and moved West across the plains hunting buffalo. The Arapaho are another good candidate, if the effigies can be attributed to any named language-speaking people, he said.
If some of the effigies are around 2,000 years old, then perhaps a group known as the Avonlea complex was their builder. Complex in this case is an archaeological term to describe a shared way of living. And the Avonlea have the same distribution as the effigies, running from Minnesota westward and up into Canada, Fosha said.
Sundstrom says the few recorded medicine wheels found in South Dakota, in Hand and Custer counties with another said to have been in Corson County, can be identified with Algonkian-speaking peoples, such as the Blackfoot, Cheyenne and Arapaho.
More than sixty such medicine wheels from those tribes can be found in Canada, Montana and North Dakota. The scarcity of similar features in South Dakota is not surprising as the Cheyenne and Arapaho only lived in the state for a few centuries, she said.
Northern Cheyenne oral tradition also includes references to an old village near Freeman, South Dakota, and a swan effigy found there. The effigy is said to honor a leader named Swan whose band moved across the Missouri River heading toward the Black Hills. The effigy's head points west, indicating the direction of their travel, the tradition says.
Hannus, among others, said there wasn't one single group of effigy builders. The practice could have been common among various Plains tribes.
But the most daunting question, because it encompasses aspects of all the others combined, is that of motive. Why draw large images with stone across the prairie landscape?
Sundstrom's report lists several possible interpretations for the sites including memorials to important people or events, identifiers of particular social groups, shrines related to war, hunting and planting, and astronomical observatories.
"None of these are mutually exclusive and none have been decisively studied archaeologically," her report says.
Brace takes a practical point of view, saying that many of the animal effigies were environmental indicators, acting as landmarks or identifying the location of resources.
With so many questions and so few clues, the enigma of the stone effigies may be a mystery that will never be entirely solved. Sundstrom said one major issue in understanding the effigies, even the ones with oral traditions, is the natural disconnect inherent in translating ideas between two cultures. With the older effigies, it's possible the connection with the past and the effigies' purposes is already lost.
"As with a lot of archaeology we have to say 'I don't know, but this is as far as the data takes me,'" she said.
Information from: Pierre Capital Journal, http://www.capjournal.com