28 Apr '15, 11pm

@OpenROV Huge, shallow, full of early sharks and fish and plants. Muddy salt water.

@OpenROV Huge, shallow, full of early sharks and fish and plants. Muddy salt water.

Devonian Fossil Case Illinois State Museum Exhibit 417–354 Million Years Ago Devonian Period During the Devonian, a shallow sea covered Illinois and much of North America. To the east, the Appalachian Mountains were being forced up as the North America collided with Africa. Mountains were forming in Arkansas and southern Missouri. Erosion from them covered the sea bottom in southern Illinois with silt and mud. Warm inland seas covered Illinois during the Devonian, the "Age of Fish." On the sea floor, coral and lime-secreting sponges called stromatoporoids formed large reef-like patches. Weather events can leave a record in the rocks. Tropical storms would periodically flatten and bury these underwater environments. Organisms colonizing the new, surface started the cycle over again. This rhythmic change in the environment and species is recorded in the distinct bedding plan...

Full article: http://www.museum.state.il.us/exhibits/changes/htmls/trop...

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