Rocket and Raven study photos from Grand Canyon National Park. Raven spots shells in the rock walls.
"Shells way up on a canyon wall?" Rocket asks. "How did they get up there?"
Raven zooms in. "What do you notice? These shells came from sea animals."
Nova hovers over the map. "What kind of place do sea animals need?" she asks.
Many rock layers at Grand Canyon are full of sea fossils, like shells and sponges.
Sea animals lived in the sea. So those layers formed under seawater long ago.
Other layers hold footprints of animals that walked over big sand dunes.
There are no dinosaur fossils in Grand Canyon. The rocks are older than the oldest known dinosaurs.
At Fossil Butte National Monument in Wyoming, scientists found fossil palm trees and crocodile relatives.
They lived there about 52 million years ago. Back then, the area was warm and wet.
Today it is a dry grassland with sagebrush. Fossils show how much it changed.
| Fossil found | Where | Clue about the past |
|---|---|---|
| Sea shells and sponges | Grand Canyon, Arizona | A sea covered the area |
| Footprints in sandstone | Grand Canyon, Arizona | Animals walked on sand dunes |
| Palm trees | Fossil Butte, Wyoming | The climate was warm and wet |
| Statement | True or false? |
|---|---|
| Fossils can tell us what a place was like long ago. | ? |
| Grand Canyon has many dinosaur fossils. | ? |
| Fossil Butte was once warm and wet. | ? |
Living things need the right kind of place.
Sea animals need seawater. Palm trees need a warm place.
So when we find their fossils, we learn what the place was like back then.
A place can change a lot over millions of years.
| Then and now | True or false? |
|---|---|
| Fossil Butte is a dry grassland today. | ? |
| Grand Canyon rocks are older than the oldest known dinosaurs. | ? |
| A place always stays the same over millions of years. | ? |
You read the past like a paleontologist! Tomorrow you solve a fossil mystery with data.