The marine turtles of the Late Cretaceous include many large, spectacular forms. The largest, Archelon, reached twelve feet in length, with a large head and hooked beak. The limbs were modified to serve as powerful paddles, of which the front flippers were the major source of locomotion. The head probably could not be withdrawn but protection was afforded by a series of scutes (bony armor).

Present day turtles could be called “living fossils”, as they have changed little during the past millions of years.

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