Why should fossils be preserved?
Fossils are for everyone — children and adults, amateur and professional paleontologists. From fossils we learn about the history of life, but much of the story is yet to be written. Fossils from public lands are an educational and scientific resource for our generation and those yet to come. Scientifically significant fossils on U.S. federal lands belong to all the people of the United States, and other countries have similar policies. They should not be removed from the public domain, but preserved for the enjoyment and education of all.
Learn about the law regarding fossils in the U.S. >
How are vertebrate fossils different from other fossils?
Vertebrates are animals with backbones. That includes mammals, reptiles, birds, fish, amphibians and anything with bones. A vertebrate fossil doesn’t necessarily have to be bone, however – it could be scales, teeth, eggs, claws, feces or even footprints left behind by vertebrate animals.
Vertebrates are rare and often unique in the fossil record, so any specimen could be vital to scientific research. If you think you have a vertebrate fossil, contact us.
Invertebrate and plant fossils are much more common, and in some places fossilized clam shells, snails or coral are hard to miss. This doesn’t mean all invertebrate and plant fossils are unimportant; in fact, rare and well-preserved plant and invertebrate fossils are equally important to science. We mention it because some invertebrates are so common that the odds are, if you find a fossil, it’s one of these common invertebrates. In that case, there’s no need to worry that science is missing out – in all likelihood, many specimens of its kind already exist in paleontological collections.
How can I start my own fossil collection?
Fossil collecting opportunities vary around the world, and it is very important to always get permission from landowners and follow local, state, and federal laws. Please read The Paleontological Society Code of Fossil Collecting before searching for fossils. That way you know that if you follow the guidelines, your collecting will be fun and interesting for you, and helpful rather than potentially harmful to the field of paleontology.
Another thing you can do is read a book on fossil collecting guidelines. We recommend Collecting the Natural World: Legal Requirements and Personal Liability for Collecting Plants, Animals, Rocks, Minerals, Fossils, and Artifacts, by Donald Wolberg and Patsy Reinard.
Younger readers will enjoy The Fossil Factory: A Kid’s Guide to Digging Up Dinosaurs, Exploring Evolution, and Finding Fossils, by Niles Eldredge, Gregory Eldredge and Douglas Eldredge.
How can you tell if something is a fossil?
Paleontologists recognize fossils based on their shape, their structure, and sometimes the material they are made of. Since fossils are the remains of ancient life, paleontologists study the shape, structure, and materials of living things today. This helps paleontologists recognize fossils that are the remains of living things from tens of thousands to millions of years old.
How do we know how old a fossil is?
Fossils are usually preserved in sedimentary rocks, which are usually found in layers. These layers form when sediment (clay, silt, sand, etc.) falls out of suspension in some other medium like air, water, or ice. The layers form when sediment is deposited in the same place time and time again. If you think about how that works, the layers on the bottom must be the oldest because they had to be there for the next layer to be laid down on top. This principle of superposition, that the oldest layers of rock are on the bottom, is a powerful tool for telling relative time. With it, paleontologists can tell which fossil organisms lived and died before others.
Paleontologists can put numerical dates on their relative time scale by using a method called radiometric dating. The basic idea is that rocks that cool from a molten state contain naturally-occurring radioactive elements that break down into other stable materials (daughter products) at known rates. This is known as radioactive decay. Once this rate is known, geologists can calculate the length of time over which decay has been occurring by measuring the amount of radioactive parent element and the amount of stable daughter products. The trick is that this method is usually only used on rocks that were molten, and these cooled rocks don’t usually contain fossils. We can use this method when lavas and ash fall deposits form between layers of sedimentary rock that contain fossils. If we can put dates on the datable deposits above and below a sedimentary layer containing fossils, we know our fossils must have been deposited between those two dates.
How do you identify fossils that you find?
Vertebrate paleontologists spend a great deal of time studying the anatomy of living animals so that they can compare the bones and teeth of living animals to those of fossil animals. We also compare the bones and teeth of newly discovered fossils to those that have been discovered before. If they are very similar to animals that have been described before, we figure that they are new finds of the same animal. If they are different, and we are sure we have compared them to all of the other fossils and recent animals, we can name a new species for the new fossil.
How do you know where to look for fossils?
One of the best ways to find fossils is to look where they have been found before. That’s why paleontologists often go back to the same places over and over again to look for fossils. Another way to find fossils is to look at maps that have been made by geologists for rocks that are likely to have fossils that you are interested in. For instance, if you wanted to find dinosaur fossils, you would look for rocks that were deposited on land during the period of time when dinosaurs lived (Mesozoic) because that is when and where dinosaurs lived and probably died. The other way to find fossils is to go places where people haven’t mapped the rocks before, and just see what you can find!