Pottawattamie County has played a significant part in many critical historical events including: being the home to an early and extensive Native American Culture, route of the Lewis and Clark Corps of Discovery Expedition, crossing of the Mormon Trail, the railroad and western expansion, and evidence of one of the oldest archeological human burial sites in Iowa, “Turin Man,” over 4,700 years ago. Pottawattamie County grew out of the Pottawattamie Purchase of 1847 and is named after the Pottawattamie tribe that originally possessed the Iowa Territory. Pottawattamie means “Keepers of the Council Fires,” or “Blowers of Fire.”
Perhaps most unique to Pottawattamie County, however, is the earth itself. Have you looked closely at the rising and falling hillsides and bluffs around you? Have you wondered at the “catsteps” or dramatic terraces that stack, one upon the other, toward the horizon? This rare environment that surrounds you is known as the Loess Hills.
Loess (pronounced “luss”) is German meaning loose or crumbly. The Loess Hills of Iowa were formed between 14,000 and 24,000 years ago, deposited by wind (eolian) during the last great Ice Age. The irregular topography consists of many exaggerated landforms such as ridge crests, called “peaks” and “saddles.” Steep angles, zigzags, sidespurs, and deep crevasses have been carved over time. These extreme formations were created by the prevailing westerly winds that blew across the Missouri River flood plains. Great clouds of “glacial silt” accumulated in deep beds and bluffs, forming the present fragile landscape that we see. The Loess Hills are considered a “world class” geological formation, found at this depth (over 200 feet) in only two places in the world, western Iowa and in Shaanxi, China. The lighted metal sculptures at the entrance to this area and welcome center symbolize “sections” or contours in the landscape, based on this rare geological detail.
The seasons continue to change the Loess Hills. The Loess soil, without significant clay to bind the silt particles together, allows for the rapid movement of water. For this reason, it is “surprising” to find many arid or dry-loving plants that thrive in this ecology. Yucca, the image of which appears as a continuous patterned band around the building, is a prime example. Erosion is another dramatic effect of weather and water throughout the Loess Hills.
The Loess Hills support a wide and abundant variety of unique plants and animals in what remains one of Iowa’s best and last examples of virgin prairie. It is, in fact, the largest concentration of mixed grass prairie in the United States. Many species of plants including the buffalo berry, Loess Hills fern, soapweed and skeletonweed are found in Iowa only in the Loess Hills. Other native prairie plants and several endangered species of animals, such as the grasshopper mouse, plains pocket mouse and Great Plains skink are represented in text and images on terra cotta blocks in the building’s interior. These are just a few of the species that inhabit the Loess Hills because of the special characteristics of its ecology.
The Native American Indians that once lived throughout the Loess Hills, as well as those that still live in Pottawattamie County, consider the Loess Hills a “sacred” place, so special that no tribe or group could control it. Today, more and more attention is being paid to the care and conservation of the Loess Hills.