History of mammals and dinosaurs co-existence.

A slab of sandstone found on the campus of NASA's Goddard Space Flight Center in Maryland may help scientists rewrite the history of mammal and dinosaur co-existence during the Cretaceous era.

Detail view of a cast from the sandstone slab imprinted with more than 70 dinosaur and mammal tracks discovered at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Credit: NASA's Goddard Space Flight Center/Rebecca Roth

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https://www.sciencedaily.com/releases/2018/01/180131110345.htm