Template:POTD/2014-03-23
A panorama of the east face of hills showing strata from the John Day Formation in the Painted Hills Unit of the John Day Fossil Beds National Monument, in the U.S. state of Oregon. The strata, which vary in age from 18 million to 39 million years, were formed mainly from ashfalls from volcanoes to the west. The sediment layers vary in their chemical composition and color owing to the ash and other debris falling during varied climatic and volcanic conditions.Photograph: Finetooth