Loess is a wind blown and deposited silt from the glacial ages found in many areas once covered by sheets of glacial ice. When the glaciers retreated (melted back) large areas of transported materials were left behind. The wind subsequently picked up the smaller silt sized and finer particles and deposited them in thick layers, especially along the downwind side of water courses when they dried out in the winter.
Shown above is such a deposit of loess in Sangamon, County Illinois.
Much of Illinois east of the Mississippi and Illinois rivers is covered by substantial deposits of loess, which, with other factors, creates a very rich soil.
Map from Illinois State Geological Survey
As ground water percolated through the deposit of loess it would dissolve calcium carbonate, and then recrystallize to solidify particles into nodules or concretions which are known as Loess Children or the German Loess Kindren.
Native peoples would collect these concretions, which sometimes rattled with smaller concretions inside, as toys for their children.
Pictured below are some Loess Children we collected at the site above.
The large dark rock is a glacial tillite
Almost vertical cliff form by the interlocking particles of loess
Swallows often dig out the soft loess to form their nests
Loess concretion for sale on Etsy
So, there is my submission for the Challenge which does not require any BOLO’s 🙂
(A bicycle back at the garage did not make the trip way out here 🙁 )