NPS Paleontology Program
Move your cursor over the time period you wish to know more about.  Click on the period name or the accompanying images to visit a National Park with features of that age.
 
 
Visit the Bering Land Bridge National Preserve Geology Page
Visit the Hagerman Fossil Beds National Monument Geology Page Visit the Agate Fossil Beds National Monument Geology Page Visit the Badlands National Park Geology Page Visit the Fossil Butte National Monument Geology Page Visit the Theodore Roosevelt National Park Geology Page
Visit the Big Bend National Park Geology Page
Visit the Dinosaur National Monument Geology Page Geology Page
Visit the Petrified Forest National Park Geology Page
Visit the Guadalupe National Park Geology Page
Visit the Grand Canyon National Park Geology Page
Visit the New River Gorge National River Geology Page
Visit the Death Valley National Park Geology Page
Visit the Delaware Water Gap National Recreation Area Geology Page
Visit the Grand Canyon National Park Geology Page
Visit the Yellowstone National Park Geology Page
Visit the Glacier National Park Geology Page
 
Geologic Time Scale
Cenozoic
Modern humans appear
Present - 2 million years ago
Abundant mammals
2 - 65 million years ago
Mesozoic
Flowering plants; dinosaur & ammoid extinctions
65-140 million years ago
First birds & mammals; abundant dinosaurs
140-205 million years ago
Abundant coniferous trees
205 - 245 million years ago
Paleozoic
Extinction of trilobites & other marine animals
245 - 290 million years ago
Fern forests; abundant insects; first reptiles
290 - 325 million years ago
Sharks; large primitive trees
325 - 355 million years ago
Amphibians & ammonoids
355 - 415 million years ago
Early plants & animals on land
415 - 440 million years ago
First fish
440 - 495 million years ago
Abundant marine invertebrates; trilobites dominant
495 - 545 million years ago
Precambrian
Primitive aquatic plants
545 - 2500 million years ago
Achean
Oldest fossils: bacteria & algae
2500 - 3800? million years ago

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