Atlas of a lost world: travels in ice age America

"From the author of Apocalyptic Planet, an unsparing, vivid, revelatory travelogue through prehistory that traces the arrival of the First People in North America twenty thousand years ago and the artifacts that enable us to imagine their lives and fates. Scientists squabble over the locations and dates for human arrival in the New World. The first explorers were few, encampments fleeting. At some point in time, between twenty and forty thousand years ago, sea levels were low enough that a vast land bridge was exposed between Asia and North America. But the land bridge was not the only way across. This book upends our notions of where these people came from and who they were. The unpeopled continent they reached was inhabited by megafauna--mastodons, sloths, mammoths, saber-toothed cats, lions, bison, and bears. The First People were not docile--Paleolithic spear points are still encrusted with the protein of their prey--but they were wildly outnumbered and many were prey to the much larger animals. This is a chronicle of the last millennia of the Ice Age, the gradual oscillations and retreat of glaciers, the clues and traces that document the first encounters of early humans, and the animals whose presence governed the humans' chances for survival"--