The relative density of use is reflected in the archaeological record.
There is increasing evidence for use of ground stone for processing plants during this period, blurring its relation to what some archaeologists call the archaic.
Archaic represents an economic pattern of post-megafauna broad spectrum plant and animal gathering and hunting.
People repeat similar actions in specific locations, and the result is a site.
Archaeological sites are fragile because their scientific value is not just in the artifacts and features, but in the patterns of these in relation to each other.
The material remains of past patterned activities is the primary data used by archaeologists to reconstruct past human behavior and decisions.
Archaeological sites are systemic because they contain data derived form patterned behavior.
Organization Oregon's past is organized into periods that have a chronological and conceptual framework that are applied statewide with phases embedded in them that have geographical constraints.
Human populations appear in the archaeological record at the end of the last Ice Age.
This approximately corresponds to a climatic shift towards wetter and cooler conditions as well.