More shark species are known from the Cretaceous Western Interior Seaway deposits of South Dakota than other states with rocks from the same environment like those of Kansas .
However , one South Dakotan individual was 6 -- 7 meters ( 20 -- 23 ft ) long .
More shark species are known from the Cretaceous Western Interior Seaway deposits of South Dakotan   than other states with rocks from the same environment like those of Kansas .
However , one South Dakotan individual was 6 -- 7 meters ( 20 -- 23 ft ) long .