In the Black Hills town of Hot Springs, South Dakota, mammoth bones were found in 1974, and what they lay in was a trap. In the Late Pleistocene a cavern in the Minnelusa Limestone collapsed into a sinkhole at least 65 feet deep, and warm artesian water rising through a natural chimney filled it with a steep-sided pond. Mammoths came for the warm water and the plants, and some could not climb back out over the slippery Spearfish Shale when the water was low; they died of starvation, exhaustion or drowning, and over 350 to 700 years the pond slowly filled with silt over them. By 2016 the remains of 61 mammoths had been recovered, 58 Columbian and 3 woolly, and their footprints are in the sediment too. A building now encloses the sinkhole, which is still being excavated, with a museum and an extensive collection of mammoth remains around the active dig.
61 mammoths trapped in a sinkhole pond · Late Pleistocene
This ground is protected. Photograph it, record it, leave it where it lies. On US federal land the Paleontological Resources Preservation Act 2009 makes collecting vertebrate fossils an offence, and penalties are real.
Other places on the map within a couple of hours.
