What are fossils

layers by different kinds of soil or in units – usually about 10 centimeters or so. We strip off square by square of the soil and try to leave the bones up on pedestals, at least the bigger bones. On the pedestals you can eventually see the relationship between all the bones. All the soil that we dig around the bones in each of the square units is then bucketed to the screens. We water-wash all the soil through window screens because we don’t just have the big bones, we also have the bones of smaller animals that lived on the site, and they tell a lot about the environment and the times. We do all the screening and map the bones exactly and they have to be packed well to
avoid water.

Q: What do you do with the bones once you get them to the museum?
A: We bring the bones back to the museum. The big bones have to be cleaned and dried slowly for a couple of months. Some others are selected for radio carbon dating to see how old they actually are and some are set back with no kind of chemical preparation because in the future we may want to do further testing. Most of the rest of the bones then have a preservative put in them to make sure that they survive. The bones have been in the ground for thousands of years, and they could dry out and crack, so we want to try to prevent that. All the soil from the site that we screened once, we bring it back to the lab and volunteers re-screen it. It takes out a lot more of the dirt and leaves all the bone, the rock, and pebbles. Then they go to the microscope, and they pick out all the small bones with little tweezers one by one. We had a lot of material from the Pipe Creek Junior Quarry. All the frog bones were found through the screening. And at the mastodon sites we do the same thing.


Back What does a paleontologist do? How do paleontologists get fossils? How do they study them? Mr. Ron Richards is the curator of paleobiology and chief curator of natural history at the Indiana State Museum. He tells about finding fossils at a dig site. Q: How do you keep track of what is going on at a dig site? A: We want to be able to reconstruct the site on paper the way we found it because when you dig a site, you destroy it. You can only dig it once. If you don’t have notes and records, then you don’t know what happened. Years ago people would just rip bones out of the ground just to look at the bones and see how magnificent they were. Nowadays, information and knowledge are more important. We have to know the world and think it’s important to know the world. Today we try to learn as much about the site as we can. Q: What is the biggest challenge that you face on a dig? A: The site is confusing when we get there because you have what naturally occurred and what some big piece of machinery done. So what we have to figure out first is what is has been disturbed by the machinery and what is lying in the original position in the ground. We want to get to the real evidence of what is lying in the ground as it was originally. Q: What do you actually do on the dig? What is your process? A: Typically we will strip off all the disturbed soil so we can see where the actual skeleton lays. If we see that there is a pile of dark soil that got scraped by the machinery or had people walking on it, we want to strip all that off. Then we will grid it off so that we can plot exactly where every bone comes from. We go down in	Ron Richards holds a mastodon tooth Mastodon bones at the Kewanna dig site
layers by different kinds of soil or in units – usually about 10 centimeters or so. We strip off square by square of the soil and try to leave the bones up on pedestals, at least the bigger bones. On the pedestals you can eventually see the relationship between all the bones. All the soil that we dig around the bones in each of the square units is then bucketed to the screens. We water-wash all the soil through window screens because we don’t just have the big bones, we also have the bones of smaller animals that lived on the site, and they tell a lot about the environment and the times. We do all the screening and map the bones exactly and they have to be packed well to avoid water. Q: What do you do with the bones once you get them to the museum? A: We bring the bones back to the museum. The big bones have to be cleaned and dried slowly for a couple of months. Some others are selected for radio carbon dating to see how old they actually are and some are set back with no kind of chemical preparation because in the future we may want to do further testing. Most of the rest of the bones then have a preservative put in them to make sure that they survive. The bones have been in the ground for thousands of years, and they could dry out and crack, so we want to try to prevent that. All the soil from the site that we screened once, we bring it back to the lab and volunteers re-screen it. It takes out a lot more of the dirt and leaves all the bone, the rock, and pebbles. Then they go to the microscope, and they pick out all the small bones with little tweezers one by one. We had a lot of material from the Pipe Creek Junior Quarry. All the frog bones were found through the screening. And at the mastodon sites we do the same thing.

	Cornell University’s Mastodon Matrix Project. Help with a real Mastodon dig in your classroom.
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