The Painted Hills Unit of the John Day National Monument is named the colorful layers in its hills. Formed in an ancient river floodplain ,the geological eras in which it was formed was between 44 million years and about 7 million years ago.

The black soil is lignite that was vegetative matter that grew along the floodplain. The gray coloring is mudstone, siltstone, and shale. The red coloring is laterite soil that formed by floodplain deposits when the area was warm and humid.  

An abundance of fossil remains of early horses, camels, and rhinoceroses in the Painted Hills unit makes the area particularly important to vertebrate paleontologists.

I arrived in the afternoon to join a couple of great photographer friends. Just before sunset we were treated to this dramatic scene as the sunlight broke through the stormy clouds. I have visited the site numerous time over many years. This evening far surpassed all my other visits.