The vascular plant emerged around 400 million years ago and started Earth's forest-building process during the Silurian geologic period ... at about the same time geologists think the earth ...

A panel of experts has spent more than a decade deliberating on how, and whether, to mark a momentous new epoch in geologic time ... Dense forests became farmland, cities rose and sprawled ...

This article was originally published with the title “ The Petrified Forests of Yellowstone Park ” in Scientific American Magazine Vol. 210 No. 4 (April 1964), p. 106 doi:10.1038 ...

Tundra gave way to forest. As the climate changed ... We base our division of geologic time on evidence of changes in the life forms present on Earth in different times. In the past, global ...

Fossilized pollen is indicative of a particular span of geologic time, so its presence can help ... providing direct evidence of the presence of cool, wet forests.” Exactly why trees don ...