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 ...

Late Ordovician Period - The Ordovician Period refers to the interval of geologic time from approximately 505 to 438 million years ago and is sometimes called the "age of marine invertebrates". Late ...

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 ...

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 ...

A new study provides compelling new evidence that a colossal 'megaflood' refilled the Mediterranean Sea, ending a period during which the Med was a vast expanse of salt flats. The study suggests the ...

And this might have changed Earth’s climate and geological history forever. Around 466 million years ago, during a period ...