Petroform

Petroforms, or also known as boulder outlines, or boulder mosaics, are the large outline of shapes that were made by arranging many rocks on the open ground into various shapes and patterns. Aboriginal groups made shapes of humans, snakes, turtles, birds, medicine wheels, and geometric shapes in prehistoric times that are still intact today. Petroform sites in North America can be found in Manitoba, Saskatchewan, Wisconsin, Wyoming, Montana, and many other states and provinces. Petroglyphs and pictographs are quite different, because petroforms are often made from large rocks and boulders over large areas of ground, unlike the smaller glyphs and graphs. Petroforms can also be used much easier and in more complex ways for astronomical predictions, mapping, and ceremonies. Petroforms are similar in some ways to medicine wheels.