Species of the genus Adocus had flattened and smoothly contoured shells with horny sculptured plates. The shells could reach a length of about 80 cm. These large freshwater turtles had an omnivore diet. They lived from the Late Cretaceous to the Late Paleocene in North America, but in Asia the were present also in the Eocene.
These turtles have been found in Cretaceous to Paleogene of United States and in Cretaceous of Kazakhstan, Tajikistan, United States and Uzbekistan.