Paleontology and geology
The Precambrian: Nova Scotia can be divided into two distinct geological regions by a large fault that runs from Cobequid Bay in the west to Cedabucto Bay in the east. Rocks of these regions are named after the microcontinents they are derived from. To the north is the Avalon Zone, to the south, the Meguma Zone. During the Precambrian, not much of Nova Scotia existed. The northwestern tip of Cape Breton Island was part of Laurentia and lay near the equator. These metamorphic rocks belong to the Grenville Group and are part of the Canadian Shield. The rest of the Avalon Zone was just beginning to form. It started as a series of island arcs off the coast of Gondwana, which lay near the South Pole. The Meguma microcontinent had not formed yet.
The Paleozoic: The microcontinents, Avalonia and Meguma, broke away from Gondwana and collided with Laurentia at separate times. Every collision created mountains and generated substantial igneous activity. Volcanoes deposited lava and ash on the surface, and magma intruded under older rocks. Shallow seas filled with trilobites, brachiopods, crinoids, graptolites, and fish covered some areas of Nova Scotia. Fossils of plants, insects, early amphibians and reptiles, and many trackways, record a landscape of swamps, wetlands, and forests on the land. By the end of this era, Nova Scotia was uplifted as all the continents collided to form Pangea.
The Mesozoic: After Pangea formed, it soon began to break up, opening the Atlantic Ocean east of Nova Scotia. This rifting created many basins, including the Bay of Fundy. In areas where the crust was very thin, lava erupted and flooded the basins. Rivers, lakes, and dunes also developed in the basins. They preserve fossils of the plants, dinosaurs, early crocodiles, and mammal-like reptiles that lived here. There are few deposits from the Mesozoic in Nova Scotia because erosion removed most of them.
The Cenozoic: There are no Tertiary age rocks on land in Nova Scotia; however, they can be found offshore on the continental shelf. Glaciers from the Quaternary shaped the modern landscape of this province. They eroded, smoothed, and gouged exposed rocks. As the glaciers melted, they deposited sediments in the shape of rounded hills, called drumlins. Quaternary rocks have yielded fossils of plants, turtles, fish, and mastodons. Marine sands with bivalve fossils on land record times when sea level was higher.