Browse Items (6 total) Tags: Colorado Browse All Browse by Tag Search Items Sort by: Title Creator Date Added Leaf Fossil leaf imprint. Tags: Brown, Colorado, Eocene, Fossils, Geology, Miocene, North America, Oligocene, Paleocene, Plants, Pliocene, Tan, Tertiary, United States Agate Small, cut and polished piece of a banded light to dark gray and light reddish-brown agate. Tags: Brown, Colorado, Geology, Gray, North America, Red, Rocks and Minerals, United States Pyrite One large partial crystal of pyrite. Tags: Colorado, Geology, North America, Rocks and Minerals, United States Porcupine, North American Tags: Animals, Colorado, Mammals, North America, United States, Zoology Bluebird, Mountain Tags: Animals, Birds, Colorado, North America, United States, Zoology Bivalve, Freshwater Tags: Animals, Bivalves, Brown, Colorado, Mollusks, North America, United States, Zoology Featured Item Dinosaur Cast containing the 4th metatarsal of the right hind foot.