Photo credit:Washington DNR/Flickr
Mima mounds are not unique to Washington.
Similar formations have been found in other US states and all across the globe, except Antarctica.
The shape, size and composition of the mounds vary from place to place.
According to this theory, each mima mound develops through the effort of many generation of gophers.
Another issue with this theory lies in the big rocks commonly found in and on top of the mounds.
These rocks are too large for gophers to move.
A competing theory suggest that the mounds resulted from the accumulation of wind-blown sediments around clumps of vegetation.
Another theory suggests that gravel and stones washed upon a melting glacier collected in depressions known as sun cups.
The remaining mounds are now designated a National Natural Landmark and protected under the Mima Mounds Natural Area Preserve.
Mima mounds are also present at the Scatter Creek Unit, located in southern Thurston County, Washington.
