Phanerozoic of Pangaea into Laurasia and Gondwana in an extinction known as the Jurassic-Cretaceous extinction. Sea levels rose, destroying fern prairies and creating shallows. Ichthyosaurs became extinct whereas sauropods, as a whole, did not; in fact, some species, like "Titanosaurus", lived until the K-T extinction. The increase in sea-levels opened up the Atlantic sea way which would continue to get larger over time. The divided world would give opportunity for the diversification of new dinosaurs. The Cretaceous is the longest period in the Mesozoic, spans from 145 million to 66 million years ago, and is divided into two epochs: Early Cretaceous,
Volcanology of Canada Jurassic and Cretaceous periods. The source for this volcanism was a long-lived and stationary area of molten rock called the New England or Great Meteor hotspot. The first event erupted kimberlite magma in the James Bay lowlands region of northern Ontario 180 million years ago, creating the Attawapiskat kimberlite field. Another kimberlite event spanned a period of 13 million years 165 to 152 million years ago, creating the Kirkland Lake kimberlite field in northeastern Ontario. Another period of kimberlite volcanism occurred in northeastern Ontario 154 to 134 million years ago, creating the Lake Timiskaming kimberlite field. As the North American