Paleowetland deposits showing black mat

Wetland deposits at the Murray Springs Paleoindian Site in southeastern Arizona. Megafaunal remains and Clovis-age artifacts dating to ~13,000 years before present have been found under the dark "black mat" layer near the middle of the exposure (just above the white Coro Marl), marking a time of significant climatic, faunal, and human transition in North America.