Late Cretaceous Western Interior Seaway
Meet the mother of all Turtles! Archelon is the largest turtle that ever lived! The Archelon reached about 12 feet long, 8 feet wide, and weighed well over 4,200 pounds. Like it's Sea Turtle cousins today the Archelon could retract its head into its shell, but could swim 30 miles an hour. Also, Archelon fed on small invertabrates of the ocean, mainly Jellyfish.
The first indications of this mammoth marine reptile were found and named by Dr. G. R. Wieland in 1895 in Pierre Shale, South Dakota. Another fossil was found in the 1970s in the same place but was even bigger. From flipper to flipper it was 16 feet wide and 13 feet long.
In Popular Culture
Archelon made a fairly well appearance in a 1966 remake of One Million Years B.C created by Hammer Film Productions. You may also see it in the final episode of Chased by Sea Monsters, hosted by Nigel Marvin, as well as The Land Before Time IV: Journey Through the Mists. It also made a very minor appearance in Dinosaur Train.