Pictured above is a Loess doll, collected from Crowley’s Ridge in the Mississippi River Valley, eastern Arkansas. A loess doll is a type of concretion, or chemically precipitated mineral mass. They grow in deposits of wind-blown sediment, known as loess, by a process of leaching and concentration of minerals within a soil. They typically form by nucleating around a particle in the loess, such as a fragment of a fossil.
They were given the name loess doll due to the whimsical shapes these concretions take, which sometimes resemble people or animals; the one above looks like a lamb to me. Aside from their charm, they are important to geologists because they’re associated with buried soils, or fossilized soils, which are useful markers for correlating land surfaces across large areas.
To see more loess dolls click here