Sauroposeidon (meaning "earthquake god lizard") is a genus of sauropod dinosaur, remains were found in the southwestern portion of the US state of Oklahoma. It lived in Early Cretaceous, a period when the sauropods of North America had diminished in both size and numbers, making it the last known giant dinosaur on the continent. While the fossils were discovered in 1994, due to their unexpected age and unusual size they were initially misclassified as pieces of petrified wood. Sauroposeidon lived on the shores of the Gulf of Mexico, in a river delta. Like other brachiosaurids, Sauroposeidon was a quadrupedal herbivore Extrapolations based on its more completely known relative Brachiosaurus indicate that the head of Sauroposeidon could reach 17 m (56 ft) in height with its neck extended, making it the tallest known dinosaur. With an estimated length of up to 34 m (110 ft) and a mass of 50–60 t (55–66 short tons), it also ranks among the longest and heaviest.