A developer had begun digging in anticipation of building a new neighborhood in Hot Springs, South Dakota when he realized that he had uncovered an area of possible interest to archeologists. And thus ensued a fascinating look into the remote past.
It turns out that a sinkhole formed in the Pleistocene era, and animals would come there to drink. The sides were sloped and slippery, and the animals would slide in and be unable to extricate themselves. To date, the remains of over 60 mammoths have been uncovered there. According to a Wikipedia article about the site, "Findings at the site include the remains of megafauna such as giant short-faced bears along with those of shrub oxen, American camel, llama, wolves, coyotes, birds, minks, ferrets, prairie dogs, voles, and moles. Invertebrate discoveries include several species of clams, snails, and slugs."
It's a fascinating site if you have the opportunity to visit!
