▁and ▁is ▁known ▁to ▁scientific ▁people ▁throughout ▁the ▁world ." ▁ ▁The ▁super int endent ▁at ▁Wind ▁C ave ▁National ▁Park ▁was ▁given ▁juris diction ▁over ▁the ▁new ▁national ▁monument , ▁but ▁day - to - day ▁super vision ▁was ▁left ▁to ▁local ▁ran ch ers . ▁ ▁De author ization ▁of ▁the ▁monument ▁Even ▁before ▁formal ▁appro val ▁of ▁the ▁new ▁national ▁monument , ▁all ▁of ▁the ▁visible ▁foss ils ▁had ▁been ▁removed , ▁many ▁by ▁George ▁We il and . ▁Ex c av ations ▁in ▁ 1 9 3 5 ▁un cover ed ▁many ▁new ▁foss ils ▁which ▁were ▁also ▁removed ▁by ▁We il and . ▁The ▁site ▁was ▁retained ▁for ▁some ▁years ▁in ▁the ▁expectation ▁that ▁er os ion ▁would ▁un cover ▁new ▁foss ils . ▁This ▁did ▁not ▁happen , ▁however , ▁and ▁on ▁September ▁ 1 , ▁ 1 9 5 7 , ▁F oss il ▁Cy c ad ▁National ▁Monument ▁was ▁transferred ▁to ▁the ▁Bureau ▁of ▁Land ▁Management . ▁In ▁ 1 9 8 0 , ▁construction ▁of ▁a ▁highway ▁through ▁the ▁site ▁un cover ed ▁more ▁foss il ▁cy c ads . ▁The ▁site ▁was ▁nominated ▁as ▁an ▁" Area ▁of ▁Crit ical ▁Environment al ▁Conc ern " ▁in ▁ 1 9 9 7 .. ▁ ▁References ▁ ▁External ▁links ▁From ▁Dak oter ra , ▁volume ▁ 6 ▁( Pro ceed ings ▁of ▁the ▁ 1 0 th ▁Conference ▁on ▁F oss il ▁Resources . ▁Rap id ▁City , ▁SD ▁May ▁ 2 0 1 4