Natural History Museum

Fossil Focus Exhibits

Ammonite Models

Life reconstructions of Placenticeras meeki and Baculites grandis, two very different ammonites that lived in the Late Cretaceous, are hanging in the Life Through Time exhibit area. Placenticeras, the coiled ammonite is 24" in diameter and Baculites, the straight ammonite, is 88" long. For more information and photos, see the Cephalopods section of our Cretaceous exhibit.

Making of a Fossil

Fossils take many forms. Learn the difference between processes such as petrification, carbonization and impressions. View case index


Ammonites are a group of mollusks that went extinct 65 million years ago. Most ammonoids had their shells coiled into a flat disk, though the earliest forms were cone shaped, and the baculites of the Cretaceous had a small coil at the end of a cone shaped shell.

Ammonite bodies resembled the modern day squid. Some ammonites grew to six feet (2 meters) in diameter. View case index


Plants have been on the planet for 400 million years. Learn about the evolution of wood and see fossilized extinct trees and ferns. (Additional plant fossils are displayed in nearly all of the cases, beginning with the Silurian, of the Life Through Time Exhibit.)

Insects—web only

Primitive, wingless, insects are first seen in the fossil record approximately 380 million years ago. Insect fossils in this web-only display date back to the Jurassic Period. They include insects in amber as well as impression fossils. View display index


Ancient cephalopods, including belemnites and ammonoids are displayed as well as specimens of their modern-day relative, the nautilus. Beautiful ammonoid fossils include specimens with chambers filled with quartz crystals and with iridescent outer shells. View case index


Ancient echinoderms, including sea lilies, sea stars, sand dollars and sea biscuits are displayed here. The collection contains some very detailed specimens of sea lilies. View case index (Many additional echinoderms are displayed in the cases of the Life Through Time Exhibit.)


Trilobites are arthropods which lived from 570-240 million years ago. Many different types of trilobites are shown here from the U.S., Africa, and Canada. View case index (Many additional trilobites are displayed in the Paleozoic cases of the Life Through Time Exhibit.)


Life Through Time Mural icon
Life Through Time Mural
Geological Timeline icon
Geological Timeline

©2006, HSU NHM | Last modified 12 October 2012