Turtles are common.

Snails occur and are similar to the snails present now.

Oreodon skulls

Camel skulls and teeth (The first two images are the same skull.)

Elomeryx or Agriochoerus, most likely the later.

Rhinoceros

Miscellaneous teeth including carnivore (early dog), deer, mesohippus (horse), and rodent

Rabbit (Paleolagus)

Miscellaneous articulated bones

Coprolites

Rodent teeth (This specimen is 9mm long.)

Mesohippus (The last two molars in the upper jaw. A young animal—the last molar is just erupting,)

   

White River Formation, Weld County Colorado

I began collecting in Weld County after joining the Hiking Club at Colorado State University in the 1960s.
My first hike was to Pawnee Buttes. (There's a photo of the buttes taken at sunrise in November in my collection
of landscape photos.) Current research puts the White River Formation starting in the Eocene and ending in the Oligocene.