Dinosaurs 101

What are fossils?

The only direct way we have of learning about dinosaurs is by studying fossils. Fossils are the remains of ancient animals and plants, the traces or impressions of living things from past geologic ages, or the traces of their activities. Fossils have been found on every continenet on earth and maybe even your neighborhood!
The word fossil comes from the Latin word fossilis, which means "dug up." Most fossils are excavated from sedimentary rock layers . Sedimentary rock is rock that has formed from sediment, like sand, mud, small pieces of rocks. Over long periods of time, these small pieces of debris are compressed (squeezed) as they are buried under more and more layers of sediment that piles up on top of it. Eventually, they are compressed into sedimentary rock. The layers that are farther down in the Earth are older than the top layers.

The fossil of a bone doesn't have any bone in it! A fossilized object has the same shape as the original object, but is chemically more like a rock.


What Do Fossils Look Like?
Fossils have the same shape that the original item had, but their color, density, and texture vary widely. A fossil's color depends on what minerals formed it. Fossils are usually heavier than the original item since they are formed entirely of minerals (they're essentially stone that has replaced the original structure). Most fossils are made of ordinary rock material, but some are more exotic, including one fossilized dinosaur bone, a Kakuru tibia, which is an opal!