Mesozoic Era

green background with text mesozoic era 252 MILLION TO 66 MILLION YEARS AGO


The Mesozoic Era (251.9 to 66.0 million years ago) was the "Age of Reptiles." During the Mesozoic, Pangaea began separating into the modern continents, and the modern Rocky Mountains rose. Dinosaurs, crocodiles, and pterosaurs ruled the land and air. As climate changed and rapid plate tectonics resulted in shallow ocean basins, sea levels rose world-wide and seas expanded across the center of North America. Large marine reptiles such as plesiosaurs, along with the coiled-shell ammonites, flourished in these seas. Common Mesozoic fossils include dinosaur bones and teeth, and diverse plant fossils.

Mesozoic Resources

The Mesozoic Era is further divided into three Periods: the Triassic, the Jurassic, and the Cretaceous. A few examples of NPS resources in each time Period are highlighted below.

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    Mesozoic “Age of Reptiles” Coloring Pages

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    Visit—Mesozoic Parks

    Every park contains some slice of geologic time. Here we highlight a few parks associated with Mesozoic Era. This is not to say that a particular park has only rocks from the specified period. Rather, rocks in selected parks exemplify a certain event or preserve fossils or rocks from a certain geologic age.

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      Part of a series of articles titled Geologic Time—Major Divisions and NPS Fossils.

      Previous: Cenozoic Era

      Next: Paleozoic Era

      Arches National Park, Badlands National Park, Big Bend National Park, Canyon de Chelly National Monument, Canyonlands National Park, Capitol Reef National Park, Chaco Culture National Historical Park, Denali National Park & Preserve, Dinosaur National Monument, Glen Canyon National Recreation Area, Katmai National Park & Preserve, Lake Clark National Park & Preserve, Mesa Verde National Park, Missouri National Recreational River, Petrified Forest National Park, Rainbow Bridge National Monument, Sequoia & Kings Canyon National Parks, Wrangell - St Elias National Park & Preserve, Wupatki National Monument, Yosemite National Park, Zion National Park more »

      Last updated: April 27, 2023