Drive by the Edgewood Rest Stop along Interstate 5 and you will notice rounded shapes in the surrounding prairie land. I often slow down to look them over. During some times of the year their appearance is more obvious, probably due to the seasonal difference in colors of grasses and weeds on the mounds compared to their lower margins. What might have caused these odd mounds?
Although I like to think that Siskiyou County is special, similar mounds exist in many other areas. They are found throughout the Pacific Northwest and all the way south to Baja California. They can be seen in our Great Plains, the mid-West and other parts of the world. They were first noticed and studied in western Washington, near a place called Mima Prairie, resulting in the name they are now known as—Mima Mounds.
Early on the possibility of a Native American origin for the mounds was studied but excavations failed to uncover artifacts or remains of prehistoric structures. Another idea was that gophers or other burrowing animals might have been responsible, but that notion had no evidence to support it. Some people suggested that they even might have been formed by landing UFOs!
