▁of ▁cal der as ▁formed ▁by ▁the ▁Y ellow stone ▁Hot spot . ▁The ▁cal der a ▁was ▁formed ▁when ▁a ▁la va ▁d ome ▁made ▁of ▁r hy ol ite ▁col lapsed ▁in ▁an ▁er u ption ▁between ▁ 1 6 . 3 7 ▁and ▁ 1 6 . 4 1   mill ion ▁years ▁ago . ▁The ▁la va ▁d ome ▁had ▁been ▁built ▁by ▁vol can ic ▁er u ptions ▁starting ▁about ▁ 1 9   mill ion ▁years ▁ago . ▁The ▁highest ▁point ▁in ▁the ▁Mc D erm itt ▁Cal der a ▁is ▁Jordan ▁M ead ow ▁Mountain , ▁part ▁of ▁the ▁Mont ana ▁Mountains , ▁which ▁is ▁ ▁at ▁its ▁peak ▁elev ation . ▁ ▁A ▁lake ▁formed ▁after ▁the ▁cal der a ▁col lapsed , ▁and ▁it ▁depos ited ▁var ved ▁sed iments , ▁di atom ite , ▁hor iz ons ▁with ▁op al ▁or ▁carbon ace ous ▁material , ▁and ▁ma fic ▁la vas . ▁Sign ific ant ▁ore ▁depos its ▁are ▁buried ▁in ▁the ▁cal der a , ▁including ▁mer cur y ▁and ▁u ran ium , ▁which ▁were ▁m ined ▁at ▁more ▁than ▁eight ▁sites ▁in ▁the ▁cal der a ▁during ▁the ▁ 2 0 th   century . ▁Mercur y ▁at ▁these ▁mines ▁was ▁extracted ▁in ▁large ▁amounts , ▁and ▁it ▁came ▁mostly ▁from ▁c inn ab ar . ▁The ▁Mc D erm itt ▁Mine , ▁located ▁on ▁the ▁eastern ▁edge ▁of ▁the ▁cal der a ▁in ▁Nev ada , ▁was ▁the ▁last