Paleozoic marine ecosystems were marked by a diverse array of symbiotic interactions that have left a lasting imprint on the evolutionary history of life. These associations, ranging from mutualistic ...

Some 390 million years ago in the ancient ocean, marine animals began colonizing depths previously uninhabited. New research indicates this underwater migration occurred in response to a permanent ...

Walcott, Charles D. 1923. "Pre-devonian paleozoic formations of the cordilleran provinces of Canada." Smithsonian Miscellaneous Collections, 75, (5) 174–377.

Materials are from the Charles Walcott Collection, and include field notes, photographs, sketches and stratagraphic sections detailing Walcott's observations and work in geology and paleontology, ...