▁Rock ▁Tower ▁Rock ▁is ▁located ▁in ▁the ▁Adel ▁Mountains ▁Vol can ic ▁Field . ▁The ▁Adel ▁Mountains ▁Vol can ic ▁Field ▁is ▁a ▁ ▁thick ▁unit ▁which ▁lies ▁un con form ably ▁on ▁top ▁of ▁C ret ace ous ▁sed iment ary ▁rock ▁of ▁the ▁Two ▁Medicine ▁Form ation ▁on ▁the ▁edge ▁of ▁the ▁Great ▁F alls ▁T ect onic ▁Zone . ▁The ▁age ▁of ▁the ▁vol can ic ▁field ▁has ▁been ▁estimated ▁to ▁range ▁from ▁ 6 0 ▁million ▁years ▁to ▁ 6 6 ▁million ▁years ▁old ▁to ▁ 8 1 ▁to ▁ 7 1 ▁million ▁years ▁old , ▁although ▁most ▁estimates ▁today ▁place ▁its ▁age ▁at ▁ 7 5 ▁million ▁years . ▁ ▁Tower ▁Rock ▁is ▁a ▁sh on kin ite ▁intr usion . ▁As ▁the ▁surrounding ▁rock ▁weather ed , ▁the ▁harder ▁sh on kin ite ▁remained ▁behind . ▁The ▁rock ▁is ▁roughly ▁ob long , ▁occup ying ▁about ▁. ▁The ▁land form ▁is ▁ ▁high , ▁and ▁consists ▁of ▁clear ▁out cro ps ▁at ▁the ▁north ▁and ▁south ▁ends ▁connected ▁by ▁a ▁broken ▁s addle ▁r idge . ▁The ▁southern ▁out c rop ▁is ▁ ▁higher ▁than ▁the ▁northern ▁out c rop . ▁At ▁its ▁highest ▁point , ▁Tower ▁Rock ▁is ▁ ▁above ▁sea ▁level . ▁ ▁Tower ▁Rock ▁is ▁heavily ▁weather ed , ▁with ▁the ▁east ▁side ▁covered ▁in ▁sc ree . ▁The ▁flat ▁areas ▁around ▁Tower ▁Rock ▁are ▁old ▁channels ▁of ▁the ▁Missouri ▁River . ▁Th in ▁to ps o il ▁covers ▁the ▁base ▁on ▁the ▁north