Archeological excavations in the Snake River Birds of Prey Area have revealed what is believed to be the oldest known prehistoric site along the river in southwest Idaho.

Judy Willig, Boise District archaeologist for the Bureau of Land Management, said test excavations have uncovered the remains of an ancient Indian encampment believed to be 9,400 years old. Prior to the discovery last summer, the earliest dated site along the Snake River in southwest Idaho was believed to be 4,600 years old, she said.Scientists have used carbon dating since the excavation last summer to determine age.

The oldest archaeological site in Idaho is Wilson Butte Cave, located northeast of Twin Falls, which dates from 10,000 to 14,000 years ago, Willig said.

Willig said the prehistoric site was discovered during test excavations that were being conducted in preparation for a road improvement project in the Snake River Birds of Prey Area, 20 miles southwest of Boise.

The BLM routinely evaluates cultural and environmental values before implementing projects that would disturb the ground, she said.

A crew of BLM archaeologists and volunteers from Linn Benton Community College in Oregon dug test excavations at five sites in the area of the proposed road improvement, she said.

Willig said her crew, digging between large boulders 50 feet from the river, found a site that exhibited three distinct periods of occupation.

At the lowest, and thus the oldest, level of occupation, the crew found several large leaf-shaped bifaces, which are stone tools that have been flaked on both sides.

They also found abrading tools and stones that appear to have been used for grinding food.