As a period of geologic time, the boundaries of the Triassic are defined on the basis of rocks and the fossil record. It was the German geologist Friedrich August von Alberti who first marked the ...

The Cretaceous is a geological period that began 145 million years ago and ended 66 million years ago. It is the last period in the Mesozoic Era. It comes after the Jurassic Period and before the ...

According to this view, a once-tumultuous period of change had slowed to ... aspects of the forces Lyell believed had operated over geological time to produce the world we see now.

Scientists use the evidence recorded within rocks throughout geologic time to reconstruct a picture of earth's history. Amateurs, too, can look at local rocks to learn about what life was like in the ...

John Wesley Powell A professor of geology at Illinois Wesleyan ... A shallow sea advances and retreats several times during this period, leaving behind the layers named Kaibab Limestone, Toroweap ...

Work is under way at the International Union of Geological Sciences (IUGS) to define the Anthropocene, the period from 1950 that is marked by the human impact on the Earth’s environment ...