Plesiosauria Plesiosauria The Plesiosauria (; Greek: πλησίος, "plesios", meaning "near to" and "sauros", meaning "lizard") or plesiosaurs are an order or clade of Mesozoic marine reptiles (marine Sauropsida), belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century,
Cretaceous Dawn Cretaceous Dawn Cretaceous Dawn is a science-fiction novel by sibling scientists Lisa M. Graziano and Michael S. A. Graziano, published in 2008 by Leapfrog Press (initially published as 'Hell Creek: 65 Million Years in the Past, the Journey Begins' under Trafford Publishing in 2006. The book contains 304 pages. Its story is set to a modern time and also to the prehistory of 65 million years ago (at the end of the Cretaceous era). It starts in the physics laboratory, where long-extinct beetles start to appear. Four people and a dog are then hurled 65 million years through the deep