Petroforms are shapes and patterns made from arranging large rocks and boulders, often over large areas of open ground, unlike the smaller petroglyphs and graphs which are inscribed on rock surfaces. They were originally made in North America by native peoples for astronomical, religious, sacred, healing, mnemonic devices, and teaching purposes. The specific names of these rock formations and the uses varied by political and religious group.
Some of the North American petroform shapes are over 2,500 years old. It is difficult to date all of them accurately because of a lack of soil deposits in some areas. There are claims that some petroforms are up to 8,000 years. Like the petroglyphs, many petroforms have complex and lengthy teachings that have been passed down orally by the Ojibway, other First Nations, and the Midewiwin (Grand Medicine Society). Some teachings may have been lost, along with the peoples that originally made some of the oldest petroforms in North America. In some North American States and Provinces, there are laws to protect these important archaeological and historical sites. Vandalism has occurred in the past, and careful protection of these interesting sites is needed. Perhaps some native elders have decided to keep these areas hidden or secret to avoid the possible destruction or altering of sacred sites and memories. One can learn far more about these ancient peoples when there is greater respect given to the ancient ways and artifacts left behind so long ago. Ancient civilizations thrived in North and South America, with grand architecture, math, trading networks, trails, canoes, governing structures, astronomy, symbol making, scrolls, mounds, and more. All of this occurred long before the arrival of Europeans in the 1500s and 1600s. There were very few studies or specific mention of Manitoba petroform sites until the 1900s. The first detailed studies and descriptions of some sites in Manitoba were done by Dr. J Steinbring and R. Sutton after the 1950s.
The first stone phase at Stonehenge has been dated to about 2600 BCE. Stone circles are still being made in Wales as part of the Eisteddfod movement, which incorporates this among other elements from the Druidic revival. Desert kites were used by 5000 BCE; they fell out of use in the Neolithic as prey populations declined and the human population rose.
Presently, many Ojibway or Anishinaabe ceremonies in North America involve the making of turtle shaped fire pits for sacred fires. In some instances, rocks are aligned near the entrance and fire of sweat lodge ceremonies that symbolize the moon, the sun and other things. Rock piles are still made to mark trails and important locations. A large turtle petroform of piled up boulders was recently made in the Whiteshell Park area of Manitoba.
Many petroform sites are important archaeological areas that need to be protected from vandals and misuse. In the past, many petroform sites have been disrespected and even destroyed. More education is needed to ensure that petroforms are not neglected or damaged by excessive numbers of visitors to these sites. In some cases, sacred, intact, remote sites should not be disturbed at all, except for important research and exclusive ceremonies. Petroforms, effigies, and other rock art can easily be unintentionally destroyed. Trails should not be made to intact and important historical sites. Rare and significant locations should not be indicated by conspicuous signs. In the Arctic it has been necessary to ask visitors to avoid confusing the archaeological record by putting up inuksuit of their own.
One of the locations of petroform sites, including effigies, is in Southeastern Manitoba, in Whiteshell Provincial Park, Canada. Whiteshell Park is named after the white cowrie shells used by some Anishinaabe peoples in ceremonies. The natural landscape of the park, with many large boulders left behind after the last ice age, gave humans the opportunity to arrange them into many human made patterns. Some boulders appear to be carved, chipped, or altered to look like turtle heads and other animals. Petroform shapes were used to guide travelers, point out the directions, for astronomy, as memory devices, and for ceremonial use. Different colours of rocks were used in some of the petroforms. Petroforms provide a way to memorize long oral stories and ideas associated with the shapes, the number of rocks, and the geometrical patterns of the rocks. Some common shapes are turtles and snakes, along with various circles.
These ancient sites are in need of protection from anyone who might accidentally or purposely move any of these ancient rocks that would destroy their astronomical alignments. Specific laws are set up to protect them from vandals, and to preserve them intact for generations to come.
The Southeastern Manitoba sites contain all the many variations of petroforms from across North America, which suggests that many of these rock art shapes originated there, in the central area of the North American continent. The Whiteshell River runs into the Winnipeg River which is the only water route for prehistoric travelers and later fur traders to canoe directly across the Canadian Shield between Lake Winnipeg and Lake Superior. The two rivers meet in this park and funneled prehistoric native traders from across the western prairie rivers, from the northern lakes, from south along the Red River, and from the Eastern Great Lakes. The Canadian Shield would have been an ideal place to mine and quarry various types of rock for tools and arrow heads.
There are many unknown questions about these fascinating rock shapes that are found in the boreal forests of Manitoba, on very large, bare, flat, surfaces of the Canadian Shield granite rock ridges. The granite was made smooth and flat due to the last ice age as large glaciers passed over the ridges. A large nine acre site exists in the Whiteshell Provincial Park and may possibly be the largest, intact petroform site in North America. This site is protected by the Province of Manitoba. There are also many other smaller sites in the park, and some sites elsewhere in Manitoba, North Dakota, Montana, Wisconsin, etc. The word "Manitoba" possibly comes from two Ojibway words meaning where the Spirit, or Manitou, sits. The locations of these petroforms are considered sacred ground by many, and the area was used for ceremonies, to pass along stories, share knowledge, and for elders to gather. One story indicates that this is the general area where the first human was lowered to the Earth. Whiteshell Park has some of the oldest granite bedrock areas on Earth that are mostly composed of a pink coloured granite, or smooth granite ridges, sometimes perfectly bare and flat, and sometimes a mix of red and grey granite. There are some very large flat areas of this pink, or red coloured, felsic granite that were excellent areas for aboriginal peoples to regularly gather in large numbers without causing a lot of muddy trails and ground. Some of the granite rock is about 3.8 billion years old. The very large flat surfaces of granite resemble a concrete city scape, which provided an ideal place for many prehistoric travelers and traders to gather on dry, open, flat, and high ground.
The Canadian Shield is an ancient bedrock of mountains that have been scraped down to smaller ridges by many ice ages. These ridges would have been excellent ancient highways to walk across a land of wetter areas, dense forests, lakes, and away from the main river canoe routes. Native peoples used the landscape in a reasonable and wise way, that allowed them to more easily move in search of food, for travel, for gatherings, for ceremonies, and for exploring. These ancient rock ridges became valuable routes that snake through the thick forests and across wet and difficult terrain. Petroforms made upon these granite ridges would have been partially a natural outcome based on the importance and use of the ridges for practical reasons and the abundance of glacial till and boulders to make the petroforms. The Whiteshell River and Winnipeg River routes were used by natives, fur traders, and trappers, and were the main routes to the western prairies from the Eastern Great Lakes and rivers. The petroforms found in the Whiteshell River area are close enough to the canoe routes or river highways that native peoples needed and used.
Other very similar rock circles and medicine wheels can be found across North America, but sites elsewhere do not have the diversity of shapes that the Whiteshell Park sites have. The Whiteshell Provincial Park is named after a white shell, or the miigis shell (a cowrie shell) that was very important to many native peoples across North America and elsewhere in the world. These shells were used for ceremonies and they are found naturally from the shores of the Pacific Ocean. The shells were a part of an extensive prehistoric trading network across North America. Copper, flint, and other types of minerals were also used and traded from far away. Stories written on birch bark scrolls by the midewiwin document some of the history of Ojibway migrations and the discovery of white miigis shells along Lake Superior and elsewhere.
There are areas in and around Turtle Mountain Provincial Park that have many medicine wheels and other large petroform shapes. The Turtle mountains are a hilly, rocky terrain, with many small lakes. The glacial till left behind provided plenty of rocks and boulders to pile, line up, and to make many medicine wheels and petroforms. The lack of agriculture in the area helped to protect many petroforms from destruction. The Turtle Mountains are part of the Mandan trail, and the Sioux also came through the area. The landscape features, including a long natural ridge through North Dakota, named as a serpent, were known and named by native peoples. Natural ridges, hills, and human made mounds were also used for astronomical and burial purposes. Higher areas provided an easier way to observe the horizon, sky, sun, moon, planets, and stars. In addition, higher areas were necessary to keep watch for defensive purposes, similar to old churches and castles in towns and villages.
The petroform sites in Wisconsin are being studied more closely, and can be dated more easily because of soil deposits over centuries. Many other sites have no layers of soil deposited around the petroforms. Forested areas and soil cover have partially protected many of the petroforms in Wisconsin and Minnesota. In many areas across the prairies, large circular medicine wheels were made as astronomical devices, directional maps, and for ceremonial use. Some of these medicine wheels are large, and many were destroyed for agricultural needs by clearing the grasslands of any rocks. Some are intact, such as in the Turtle Mountains, and other sandy, rocky, or more remote areas that had less crop farms and settlements. Mound building was also associated in some way with petroform use. Petroforms originally predated the use of mounds and other human-made earthen works that required more time and effort. Although mound building could have originally been necessary and practical to provide some higher ground during floods. There is some speculation that larger mounds would have served as dikes and defensive fortifications, including providing higher ground to keep watch.