" SHERIDEN CAVE, OHIO: There are [Younger Dryas Boundary] peaks in magnetic spherules, meltglass, nanodiamonds, Pt, and Ir. A charcoal-rich black mat dates to the [Younger Dryas] onset and contains peak abundances of charcoal, AC/soot, carbon spherules, and nanodiamonds that are closely associated with the last known Clovis artifacts in the cave. The black-mat layer is in direct contact with the wildfire-charred bones of two mega-mammals, the flat-headed peccary (Platygonus compressus) and the giant beaver (Castoroidies ohioensis), that are the last known examples anywhere in the world of those extinct species. "
― Graham Hancock , America Before: The Key to Earth's Lost Civilization
![Graham Hancock quote : SHERIDEN CAVE, OHIO: There are [Younger Dryas Boundary] peaks in magnetic spherules, meltglass, nanodiamonds, Pt, and Ir. A charcoal-rich black mat dates to the [Younger Dryas] onset and contains peak abundances of charcoal, AC/soot, carbon spherules, and nanodiamonds that are closely associated with the last known Clovis artifacts in the cave. The black-mat layer is in direct contact with the wildfire-charred bones of two mega-mammals, the flat-headed peccary (<i>Platygonus compressus</i>) and the giant beaver (<i>Castoroidies ohioensis</i>), that are the last known examples anywhere in the world of those extinct species.](/image/906525.jpg)