Jurassic Era

THE JURASSIC PERIOD extended from about 199 million years ago to 145 million years ago. This geological time period constitutes the middle of the Mesozoic era, also known as the Age of Dinosaurs. The start of the period is marked by the major Triassic-Jurassic extinction event. This period was named by Alexandre Brogniart for the extensive marine limestone exposures of the Jura Mountains, in the region where Germany, France and Switzerland meet.

During the early Jurassic, the supercontinent Pan-gaea broke up into the northern supercontinent Laur-asia and the southern supercontinent Gondwana. The Gulf of Mexico opened in the new rift between North America and what is now Mexico's Yucatan Peninsula. The Jurassic North Atlantic Ocean was relatively narrow, while the South Atlantic did not open until ...