Topography and climate    A coastal plain stretched into what is now the Atlantic; to the west lay the Appalachians and the eastern Allegheny Plateau. At the era’s onset, glaciers sometimes covered even the highest peaks, except for what’s now Delaware and lower Pennsylvania. Over the period, the weather warmed, except for a brief retreat to cold between 10,800 and 10,200 years ago. The ice melted; lakes formed and the sea rose.

Plant and animal life    Deer, bear, and other animals lived with caribou, mastodons, and other species that are now extinct or have since moved north. With the waning cold, forests and grasslands took root on ice-free land. next >>

When the first people arrived    Perhaps between 15,000 and 12,000 years ago, though this is debated. The earliest radiocarbon readings—dating to 17,000 years ago at the lowest excavation level of southwest Pennsylvania’s Meadowcroft Rockshelter—remain controversial.

Likely routes to the region    Another source of debate among archeologists. Obstacles lay in every direction. To the west, deep iceberg-strewn bodies of water stood at glacier edges. To the north, the Champlain Sea jutted inland. The rivers, swollen with meltwater, were clogged with silt, sand, and gravel. Wetlands bordered the waterways. next >>

How people lived    The newcomers acquired food by fishing, hunting, trapping, and collecting plants. The largest sites were likely residential–bases for seasonal hunts and gatherings or for colonizing forays into unfamiliar territory. The population was spread thin; long-distance trade was unlikely.

Main challenge to survival    Daunting terrain and climate.

Research milestone    The chronology of projectile point styles is the best dated and most complete in North America.

Promising research    New tools and techniques for artifact study will give a much clearer idea of how life was lived. << back