ohhh... you really shouldn't tempt me to bore people to tears with explanation... :)

Pooga said:
I believe that they are called the Leoss Hills. I wonder why? Looks like another glacial feature to me.

"Loess" ... a German term... is essentially wind-deposited silt -- blow-dirt that we sometimes see in the Prairies (just not very thick). It is a periglacial feature that forms in the region past the furthest advance of the glacial ice. In that dynamic environment, near the ice, the incomplete vegetation cover allows the newly deposited finer textured materials to be carried by the wind and it can be deposited in very thick banks often 10s of metres thick (some in China are >100m thick). The material is exceptionally well-suited to agriculture (fertile) and in the USA, corresponds what is commonly referred to as "The Corn Belt" -- which is just beyond the most southerly advance of the Pleistocene glaciations.