The ground before you is like a puzzle. A long streak of color breaks off, then seems to continue in the next hill, but at a different level. To connect the pieces, look for similar color, thickness, and sequence in a series of layers.
Ash and pumice from the ancestral Cascades and local volcanoes buried this area layer by layer. The colorful layers before you were deposited 33 million years ago. Soil formation processes affected each layer differently. Clays were formed and deeply buried, turning to stone. Underground forces lifted and faulted the strata, interrupting the symmetry.
The red in the Painted Hills is from rusty iron minerals, oxidized by long exposure. The golden layers reveal a mix of oxidized magnesium and iron, metamorphic claystone minerals. Black hash marks are rich with manganese. Each of the colors represents a different geologic process.
This valley is a gently contoured theater of geologic change, with erosion from rain the latest sculptor.