in Northwestern Plateau region. 1500 BC–1000 AD: Intermediate Horizon (or Campbell tradition) emerged among Indigenous peoples of California Shell ornaments and copper items at Indian Knoll, Kentucky evidence an extensive trade system over several millennia. 1000 BC: Athapaskan-speaking natives arrive in the North American Arctic, possibly from Siberia. 1000 BC: Pottery making widespread in the Eastern woodlands. Shield Archaic The Shield Archaic was a distinct regional tradition which existed during the climatic optimum, starting around 6,500 years ago. During this warm period, forests advanced northward and temperatures were warmer than they were in the late 20th century. It is associated with the northern frontier and transition area between boreal forest and tundra in what is now northern Saskatchewan and the Northwest Territories, near Lake Athabasca. However, the Late Shield Archaic phase (3,500–4,450 BP) has sites as far as Manitoba, and archaeologists have investigated suspected Shield Archaic sites as far away as Killarney Provincial Park near Georgian Bay in Ontario. The prominent Canadian archaeologist J. V. Wright argued in 1976 that the Shield Archaic had emerged from the Northern Plano tradition, but this was questioned by Bryan C. Gordon in a 1996 publication. Shield Archaic tools differed in design between "forest" and "tundra" sites. Pushplanes have been found, which would have been used for planing wood, bone, or antler. Shield Archaic people hunted caribou, with a focus on water crossings as hunting places. See also Archaeology of the Americas Archaic–Early Basketmaker Era List of pre-Columbian cultures List of archaeological periods (North America) Prehistoric Southwestern cultural divisions (North America) Pre-Columbian South America Mesolithic Footnotes References Further reading 1958 introductions 1950s neologisms +2 +2 2nd millennium BC 3rd millennium BC 4th millennium BC 5th millennium BC 6th millennium BC 7th millennium BC 8th millennium BC