A Pleistocene diatomaceous clay and a pumiceous ash, Yolo County ( California).

Discusses a diatomaceous clay of Pleistocene age, cored from 534-544ft, and a pumiceous ash found at a depth of 453ft in a test hole. Tests on the clay indicate that it is highly susceptible to compaction, and therefore, it could contribute, or perhaps has contributed, to land subsidence in the area of the test hole. The pumiceous ash is considered to be younger than about 450 000 yr. -from Authors