A road cut along the sloutheast side of Palmer Lake consists primarily of angular rocks, but a thick white layer is located below the uppermost layer of angular rocks. The white layer is volcanic ash.
I am not sure of the source. There are reported ash depsits to the south near Chelan and the soils of the Waterville Plateau that have been connected to Glacier Peak. I have observed that ash and it is generally coarser. I suspect this is Mazama ash from the massive Mount Mazama (Crater Lake) eruption There is widespread ash depsoits from Mazama throughout eastern and central Washington. Because layers of volcanic ash are common in the Pacific Northwest, they serve as extremely good stratigraphic markers when applied to geologic and archaeologic problems, as long as they are correctly identified and correlated. The ash is a time marker for the deposition of the talus and scree exposed on the cut slope.
