Texas Science Teacher Resource Hub

💡 What This Standard Actually Means

Fossils are time machines made of rock. When 4th graders see a fossilized seashell embedded in a piece of Texas limestone, they're looking at a clue from a past world. 4.12C is the standard where kids use fossil evidence to figure out what an environment used to look like, with a special focus on common Texas fossils.

Texas has an incredible fossil story to tell. Much of the state, including Central Texas, used to be covered by a shallow sea. We know this because the limestone in places like the Texas Hill Country is full of fossils of ammonites (extinct shelled sea creatures), crinoids (sea lilies that look like little stems with flowers), and other ocean animals. About 113 million years ago, the Glen Rose area was a coastline where dinosaurs walked through soft mud. Their footprints fossilized and you can still see dinosaur tracks at Dinosaur Valley State Park today. Way more recently, during the Ice Age (about 12,000 years ago), giant mammoths roamed Texas grasslands. Their bones have been found at places like the Waco Mammoth National Monument.

The big idea is that the kind of fossil tells you the kind of environment. Sea creatures = the area was underwater. Dinosaur tracks in old mud = the area was a soft coastline. Mammoth bones in grasslands = the area was a cool, open prairie. By the end of this unit, kids should be able to look at a fossil, name what kind of environment it suggests, and explain how Texas's environments have changed over millions of years.