Types of Fossils: When most people think of fossils they think of dinosaur skeletons and large bones, but there are many different types of fossils to be found. Sometimes people mistake markings, or impressions such as ‘dendrite’ as fossils. These are called pseudofossils. There are five basic types of fossils …. (Click Read more below)
Mold (imprint) fossils - When a leaf, feather, bone or even a body of an organism leaves an imprint on sediment, which hardens and becomes rock. Cast fossils - When minerals fill in the hollows of an animal track, a mollusk shell, or another part of an organism. Fossil fuels - Fuels formed by the remains of dead plants and animals. Actual Remains (Body fossils) - The body of an organism, with all the parts intact. Usually preserved in ice, amber, or tar. Petrified wood - When minerals replace wood or stone to create either petrified wood or a mineralized fossil.
Paleontologists, people who study fossils, generally divide them into two major types – Body fossils (a.k.a Actual remains) and Trace fossils.
Paleontologists, people who study fossils, generally divide them into two major types – Body fossils (a.k.a Actual remains) and Trace fossils.
The first type, Body fossils, are the fossilized remains of an animal or plant, like bones, shells and leaves. These can also include some Mold and Cast fossils; like most of the fossilized dinosaur skeletons and big bones we see, replacement fossils, like petrified wood, or whole body fossils - mammoths caught in ice, or insects trapped in amber.
The second type, Trace fossils (a.k.a. ichnofossils), are the geological records of the biological activity of an animal. These include fossilized nests, gastroliths, burrows, footprints, track ways, and coprolites (fossil poo).
Due to its dry desert conditions, the southwest is an excellent fossil observation area; with the State of Nevada being known for some of the most famous fossil finds (such as the Ichthyosaur (genus Shonisaurus) in the west. With the exception of vertebrate fossils (fish, reptiles, mammals, etc.) that can no longer be collected on public lands except as part of approved research efforts, collection of fossils for personal study is permissible on most public lands in Nevada. There are numerous locations throughout the state of limestone, shale and other geologic formations where fossiliferous layers can provide excellent examples of early Triassic ammonoids (Fig. 01) (squid-like creatures that lived inside an external shell), nautilus (a genus of cephalopods) , mollusks, shells, sponges and other ocean floor plants and organisms. Fossils of these types, dating back more than 240 million years, have been found in several locations throughout Nevada.
Unfortunately, many of the fossil-collecting areas around the country are dwindling due to their closure by state and government entities. Unscrupulous people have gone into these areas to remove large amounts of material for sale, necessitating this unfortunate result.