The Paleozoic Era (which means "Ancient Life") occurred from 542 to 251 million years ago (Ma), spanning approximately 291 million years. This interval of time is divided into six Periods - Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. These periods are also divided into 23 smaller units, called Epochs.

Click HERE to see the official International Stratigraphic Chart.

To learn more about the formation of the timescale, visit the official website- (http://www.stratigraphy.org)

During the Paleozoic, the earth underwent many changes, with respect to climate, geography, flora, fauna, etc. Sediments in Nebraska were generally deposited when global sea level was high and eroded during significant intervals of relatively low sea level.

In the eastern part of the state, rapid subsidence - which occurred along the Humboldt fault zone and creates the edge of the Forest City Basin - has allowed for a greater accumulation of Paleozoic sediments to develop. However, across the rest of the state, Paleozoic deposits occur as a relatively thin drape of sediment across the Precambrian basement rock.

Take a walk through Nebraska's Paleozoic history - click on the Periods listed at the left to see artistic reconstructions of what central North America looked like during the Paleozoic Era and learn about what was happening in Nebraska.