![]() ![]() ![]() Layers of rock deposited in deep lakes often contain abundant fossils of fishes, invertebrates, and reptiles. Each layer preserved the remains of life that lived during that specific interval. Due to climatic changes and natural oscillations in Earth’s orbit, these ancient rift environments would go through stages, from deep lakes to mudflats. The climate was warmer, too, and so the environment was wet and tropical. Before it was ocean, though, the rift was filled with lakes that were similar to Lake Victoria and Lake Tanganyika in today’s Great Rift Valley in Africa. ![]() The eastern coast of North America was rifting from western Africa, opening a furrow that would become the Atlantic Ocean. During the Triassic and Early Jurassic, the supercontinent Pangaea was in the process of splitting up. The sedimentary rocks here are intermittently intruded by younger volcanic rocks, indicating that this area was undergoing tremendous geological change at this time. These rocks were deposited during the Triassic and early Jurassic periods, or from roughly 230 to 190 million years ago. The Carnegie Museum’s Icarosaurus (which is a high-quality replica of the only known original fossil) is displayed in a glass case alongside many other casts and fossils from what is known as the Newark Supergroup, a large deposit of rocks that snake their way from South Carolina to New Brunswick and Nova Scotia. ![]()
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