Mosasaurs, giant marine reptiles that existed more than 66 million years ago, lived not only in the sea but also in rivers.

At the end of the Cretaceous Period, a type of giant reptile called mosasaurs occupied and dominated oceanic food webs.

The Hudson River flows from its headwaters in the Adirondack Mountains in up-state New York down to New York Harbor and into the Atlantic Ocean. It’s named after Henry Hudson, who explored in 1609 for ...