Tucked away in the earth's rocks there are often "pictures" from the past.
Many times, in ages past, animals walked through mud and left footprints. Slowly, over thousands of years, the mud hardened into rock. The footprints were preserved forever. We have found rocks in which there are footprints of dinosaurs and other animals. We have even found rocks with the footprints of prehistoric people.
Leaves of ancient plants and feathers from the first kinds of birds also fell into the mud. They, too, left prints that were preserved when the mud hardened into rock.
Ancient snails, clams, and other shelled sea creatures died and were covered up with mud. The mud hardened around them. When their soft parts rotted away, and their shells dissolved, a hole was left in the rock - a hole that exact shape of the dead animal. This hole was like a mold. Slowly, it filled up with minerals that hardened into stone. The stone was exact shape the dead animal had been.
These pictures and shapes in stone are called fossils. They tell us about the plants and animals of millions of years ago
Many times, in ages past, animals walked through mud and left footprints. Slowly, over thousands of years, the mud hardened into rock. The footprints were preserved forever. We have found rocks in which there are footprints of dinosaurs and other animals. We have even found rocks with the footprints of prehistoric people.
Leaves of ancient plants and feathers from the first kinds of birds also fell into the mud. They, too, left prints that were preserved when the mud hardened into rock.
Ancient snails, clams, and other shelled sea creatures died and were covered up with mud. The mud hardened around them. When their soft parts rotted away, and their shells dissolved, a hole was left in the rock - a hole that exact shape of the dead animal. This hole was like a mold. Slowly, it filled up with minerals that hardened into stone. The stone was exact shape the dead animal had been.
These pictures and shapes in stone are called fossils. They tell us about the plants and animals of millions of years ago
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