One of the places where I collect fossils is on my 365 acre fossil ranch, which is located in northwestern Nebraska. This property contains sediments deposited from the late Eocene to the early Oligocene epochs, ranging from 37 to 25 million years ago. During this time the area was most likely flat and covered with lakes and meandering rivers with seasonal floods hitting the area.
The area is very rich in fossil vertebrates, containing mammal, reptile, salamander and bird fossils. The most diverse of these groups though would be the mammals. There were many species of oreodont's, horses, camels, squirrels, rabbits, insectivors, pigs, dogs and nimravids(saber cat likes animals). The most common fossil found on the property are tortoise fossils.
Some pics of the fossil bearing formations on the ranch. As you can see the area has been eroded over time by water and winds, creating many steep ridges, gullies and stream cuts.