Deposits at the Drynock Slide Site, Thompson River Valley.
Clearly pointed out is the layer of white Mazama volcanic ash laid down 6,800 years ago by a gigantic eruption at Crater Lake, Oregon. The brown silty sand beneath the ash contains salmon bones and rare artifacts dating 7,500 years in age. These deposits are all overlain by a massive landslide that came down sometime after the Mazama ash fall.