245 to 208 million years ago
Uplift and erosion continued throughout the Triassic Period. No Triassic rocks are found in the Ozarks area. Erosion continued stripping away the Mississippian and Pennsylvanian sediments across the Ozark Dome.
In the west, mountain building occurred as Mexico was added to the North American continent. In the east, rifting began as Europe and Africa began to split away from North America to form the Atlantic Ocean.
The Ozarks area was still in the tropics, moving north to about 10 degrees north of the equator.
A new life form became abundant during the Triassic
- the dinosaur.