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  • Evan Walsh commented on Matthias Beckham‘s Fossil #031357 1 year ago

    1 year ago
    1 year ago

    Upper Cretaceous terrestrial rocks like the Hell Creek and Lance only really occur in western SD, north and slightly east of the Black Hills. There are some outcrops of the Fox Hills around the Missouri River, and in eastern South Dakota I believe that there are deposits of the Colorado Groups. However the entire Colorado Group (Greenhorn, Graneros, etc.) are entirley marine