Grab your rock hammer and explore a lost world

Ever since Sir Richard Owen coined the word "dinosaur" in 1842, people have been fascinated with the idea that "terrible lizards" once roamed the earth. And any American who can say "Jurassic Park" could probably name 10 dinosaur species. A growing interest in dinosaurs has led to a growing interest in fossil collecting among adults and children.

Though most people think of fossils as bones, the term is actually much broader.

Fossils are the physical evidence of anything that lived more than 10,000 years ago. This evidence can be a footprint or a trail made by some creature long ago. It can also be the impression of a shell or a plant, or the petrified (turned to stone) bones or soft parts of ancient organisms.

In the Northeastern United States, it's not uncommon to find what look like stone shells embedded in cliffs hundreds of miles from the seashore. And out West you can find fossilized dinosaur bones trapped in sandstone. The most fascinating part about finding a fossil is realizing that you are looking at the evidence of a creature millions of years old.

"Paleontologists are not made, they're born," says Warren Allmon. Paleontology (PALE-ee-ohn-TOHL-uh-jee) is the study of fossils, and Dr. Allmon is director of the Paleontological Research Institution in Ithaca, N.Y. He's been interested in fossils ever since he was taken to the American Museum of Natural History in New York at age 3.

Allmon says his mother helped him become a paleontologist. When he was a young teenager, his mom called the local university and found a mentor for her young fossil enthusiast.

Home-made museum

The professor told Allmon where to look for fossils in the limestone quarries of his native South Carolina. Allmon collected fossils of Eocene-era (20 million to 60 million years ago) sharks and whales.

Allmon turned the basement of his family's home into a natural history museum where his specimens were carefully labeled and displayed. His "museum" was finally complete the night before he left for college.

"If a kid has an undying interest in fossils," Allmon says, "the most important thing to do is find a mentor - someone who knows the literature and is very familiar with the state geologic surveys and the good collecting sites."

Not many people will be as focused on becoming a paleontologist as Allmon was, but his advice to any newcomer is still good: "If you live in a city," Allmon says, "you can see fossils in a museum; and if you live in the country, you can start collecting your own fossils."

If you decide to collect your own fossils, first you need to find a good place to collect them. Fossils occur only in sedimentary rocks like sandstone, limestone, or shale. Sedimentary rocks are formed from layers of mud, sand, or other sediment that builds up on the floors of lakes and oceans.

Igneous rocks (such as basalt and granite) are formed by volcanic activity - no fossils there. Metamorphic rocks began as sedimentary rocks. But then they were subjected to such heat and pressure that they were changed dramatically (marble, for example, began as limestone). No fossils there, either.

Here's what you'll need

The best way to begin is to hook up with a group. Find a fossil-hunting expedition in your area through a local natural-history museum or university.

You may want some equipment: a rock hammer (regular hammers are not safe to use on rock); safety goggles, if you're using a rock hammer; a field notebook; a permanent-ink marking pen for taking notes; a magnifying glass; a trowel; plastic bags for specimens; and - most important - a field guide to fossils.

It's very important to keep good notes on your finds. Having a fossil and not knowing where it came from is like having a painting and not knowing how old it is. For each set of fossils you collect in one place, be sure to note the location - the name of the town, at least. The specific name of the quarry or roadside is good; if you know the name of the rock formation, that's even better.

Do as the pros do

You can even write an identification number on your finds. Put a spot of white correction fluid in an inconspicuous place on your fossil, then write on it with a fine-point permanent-ink pen. Real collectors make a note card for each specimen, with the collection site, date, name of the collector, and type of fossil.

Make notes in the notebook describing where you are, where on the cliff face or stream bed you found a particular fossil, what kind of rock it was in, and a description of the fossil itself. A fossil all by itself is pretty neat, but it's more valuable if you know where it came from. For one thing, it can tell you what other fossils you can expect to find at a particular site.

Don't be disappointed if you don't come home with a dinosaur bone. The best dinosaur fossils are in places like Colorado, Wyoming, Montana, and Alberta (Canada).

So instead, learn more about the invertebrates (animals without backbones) that you're more likely to find - brachiopods, gastropods, nautiloids, trilobites - and discover what the world was like hundreds of millions of years ago.