Some landscapes, like the Grand Canyon or Yellowstone, just knock your socks off, and rightly so. Many of us have seen pictures of those magnificent grand landscapes or have visited them ourselves. Less celebrated, and often known only locally, are unique natural areas that are both ecologically rich and possessing abundant subtle beauty. Mima Mounds, located near the town of Little Rock in Thurston county, only a short distance south of Olympia (the state capital of Washington), is one such place. I was fortunate to be able to visit this landscape during the "golden hour" in the summers of 2018 and 2019, when the low rays of the evening sun spread a golden cloak over the dormant grasses.
Landscape of Uncertain Origin
The Mima Mounds is a landform called a mounded prairie. It was named in 1845 when the area was first being explored. (Mima rhymes with dime-ah) In 1966, this area of 637 acres was designated as a National Natural Landmark. The mounds are around 8 ft tall and 30 feet wide. More than thirty explanations have been proposed for their origin but none proven. At one time they were thought to be Native American graves but no human remains have ever been found. A few of the more likely explanations are listed below.
- Were the mounds created by collection of gravel and stone deposited by the melting Vashon glacier, 14,000 years ago?
- Did erosion of the gravelly sediments by glacial meltwater create them?
- Were they created by shock-waves generated by earthquakes?
- Are they the work of pocket gophers over hundreds of years as they leave behind mounds of material excavated from their tunnels?
A recent computer model suggests that a mature mound is about 500 to 700 years old when it fully developed by the incremental work of generations of gophers. The size of each mound roughly matches the territorial range of a single gopher. There are 17-30 mounds per acre. Today, hundreds of mounds are arranged in a regular pattern. However, perhaps, in the past, as many as 900,000 mounds existed in this region.
All photos by Christine Stockwell