▁ago ▁along ▁the ▁sh or elines ▁of ▁an ▁ancient ▁sea , ▁and ▁form ▁the ▁ge ological ▁setting ▁for ▁the ▁park ▁area . ▁Over ▁the ▁last ▁million ▁years ▁or ▁so , ▁these ▁layer ed ▁form ations ▁have ▁been ▁er oded , ▁disse cted ▁and ▁sculpt ed ▁by ▁the ▁Pal ux y ▁River ▁which , ▁in ▁many ▁places , ▁has ▁cut ▁down ▁to ▁resist ant ▁b eds ▁and ▁plan ed ▁off ▁s izable ▁expos ures ▁of ▁rock ▁in ▁the ▁river ▁bottom . ▁ ▁Cont ro vers y ▁ ▁Near ▁Din osa ur ▁Valley ▁State ▁Park , ▁in ▁the ▁lim estone ▁depos its ▁along ▁the ▁Pal ux y ▁River , ▁" t win ▁sets " ▁of ▁tracks ▁were ▁found ▁in ▁the ▁Glen ▁Rose ▁Form ation ▁as ▁early ▁as ▁ 1 9 0 8 . ▁These ▁foot print s ▁were ▁once ▁thought ▁to ▁be ▁evidence ▁that ▁humans ▁and ▁non - av ian ▁din osa urs ▁lived ▁at ▁the ▁same ▁time , ▁but ▁now ▁are ▁identified ▁to ▁be ▁created ▁by ▁din osa urs . ▁ ▁However , ▁young - E arth ▁creation ists ▁continue ▁to ▁believe ▁that ▁humans ▁and ▁non - av ian ▁din osa urs ▁lived ▁at ▁the ▁same ▁time , ▁a ▁notion ▁that ▁is ▁contrary ▁to ▁the ▁standard ▁view ▁of ▁the ▁ge ological ▁time ▁scale . ▁Bi ologist ▁Mass imo ▁P igli ucci ▁has ▁noted ▁that ▁ge olog ists ▁in ▁the ▁ 1 9 8 0 s ▁" clear ly ▁demonstrated ▁that ▁no ▁human ▁being ▁left ▁those ▁prints ," ▁but ▁rather ▁" they ▁were ▁in ▁fact