Paleontology and geologyPangea continued to rift apart in the Jurassic, and the Atlantic Ocean was beginning to form east of Nova Scotia. The rift valleys that formed in the Triassic continued to widen and drop down as the continental crust thinned. In the Bay of Fundy (to the west), magma intruded into older rocks and spewed from fissures, flooding the basin with lava. Volcanic rocks from these eruptions make up North Mountain, which runs along the eastern shore of the Bay of Fundy. It forms spectacular cliffs and headlands. In some places, so much lava was deposited that it cooled very slowly, forming vertical columns. During and after the eruptions, sediments were still being eroded from the surrounding highlands and accumulating in the rift basins. Floodplains, rivers, dunes, and lakes covered the valley floors and deposited conglomerates, sandstones, siltstones, and limestones. A great diversity of animals flourished in the lakes, including gastropods, bivalves, tiny crustaceans like ostracods and conchostracans, fish, sharks, and early crocodiles. Around the edges of the lakes, layers of algae built up into mounds called stromatolites, even covering logs that happened to fall in. Many different kinds of reptiles were walking around, such as sphenodontids, early sauropods and other dinosaurs, and mammal-like reptiles. They left their bones and footprints in some of the lake and river deposits. Jurassic rocks will appear on this map when you click the "SHOW" undifferentiated rock units button. The sedimentary and igneous rocks straddle the Triassic-Jurassic boundary and are often mapped together. There are no Middle or Late Jurassic rocks in Nova Scotia. |
