The term Jurassic was first imposed on strata overlying the Triassic in the Jura Mountains of Europe. Strata recognized to be of Early Jurassic age came to be called the Lias in Europe, particularly England. While the Late Triassic sequence in Europe is largely continental in origin, that of the Jurassic, including the Lias, is largely marine, reflecting a broad encroachment of the sea over Europe in Early Jurassic time. A large number of marine tetrapods have been found in Liassic rocks in Europe, as well as one very important dinosaur. Cretaceous From the Latin, creta , meaning chalk.
Continents begin to assume their modern distributions.
Rocks and sediments exhibit less erosion and metamorphosis due to their younger age. The Cretaceous contains the oldest extensive unaltered record of shallow marine sediments and fossils. Also, an extensive record of deep sea sediments exists because not all of it has been subducted. This represents a major source of evidence for interpreting ancient climates. These new predators may have triggered the retreat into deeper water of more primitive groups of attached, filter-feeding invertebrates such as brachiopods and sea lilies.