It was the end of the age of dinosaurs, and the corner of North America now called Mantua Township, New Jersey was ten miles offshore, under the Atlantic ocean. Mosasaurs dominated the sea, and sharks, rays, ammonites, turtles and fish swam through their shadows. The green sand was alive with clams, snails, crustaceans, and a whole menu of animals that would look at home on any seafood platter today – except that every species found here is long extinct.