▁in ▁sand stone ▁in ▁the ▁upper ▁Missouri ▁River ▁area . ▁He ▁thought ▁the ▁plants ▁were ▁similar ▁to ▁modern ▁ph an er og amm ic ▁plants ▁still ▁growing ▁in ▁the ▁area . ▁Maxim ilian ▁collected ▁a ▁large ▁number ▁of ▁them ▁but ▁in ▁ 1 8 3 5 ▁his ▁foss ils ▁were ▁destroyed ▁near ▁what ▁is ▁now ▁B ism ar ck ▁in ▁a ▁fire ▁on ▁the ▁steam ▁ship ▁transport ing ▁them . ▁In ▁ 1 8 4 3 ▁John ▁James ▁Aud ub on ▁collected ▁foss ils ▁like ▁pet r ified ▁wood ▁and ▁marine ▁shell s ▁in ▁the ▁area ▁but ▁the ▁spec im ens ▁were ▁of ▁low ▁quality . ▁ ▁In ▁the ▁mid ▁ 1 9 th ▁century ▁the ▁US ▁government ▁began ▁inten se ▁surve ying ▁the ▁upper ▁Missouri ▁region . ▁In ▁the ▁course ▁of ▁these ▁surve ys ▁a ▁ge ologist ▁with ▁the ▁Northern ▁Pacific ▁Rail road ▁Survey ▁named ▁John ▁Evans ▁described ▁the ▁region ▁between ▁the ▁Si oux ▁River ▁and ▁the ▁F alls ▁of ▁the ▁Missouri ▁as ▁one ▁of ▁the ▁best ▁places ▁in ▁the ▁world ▁for ▁collect ing ▁C ret ace ous ▁and ▁T ert i ary ▁foss ils . ▁ ▁Evans ▁sent ▁verte br ate ▁foss ils ▁to ▁Joseph ▁Le id y , ▁who ▁discussed ▁the ▁remains ▁in ▁a ▁pione ering ▁and ▁histor ically ▁significant ▁series ▁of ▁publications . ▁Among ▁the ▁most ▁prominent ▁figures ▁in ▁early ▁North ▁Dak ota ▁pale ont ology ▁were ▁Dr . ▁Ferdinand ▁V . ▁Hay den ▁and ▁Dr . ▁Field ing ▁Brad ford ▁Me ek . ▁New ▁York ▁ge ologist ▁W