▁old , ▁and ▁even ▁older ▁sites ▁on ▁the ▁main land . ▁University ▁of ▁Washington ▁research ers ▁have ▁undert aken ▁several ▁years ▁of ▁exc av ations ▁to ▁document ▁about ▁one ▁third ▁of ▁the ▁ ▁beach ▁complex . ▁Research ers ▁found ▁cam ps ites , ▁hear th s ▁and ▁animal ▁b ones , ▁with ▁a ▁few ▁stone ▁tools ▁and ▁pieces ▁of ▁pot tery . ▁In ▁newer ▁locations ▁the ▁team ▁documented ▁the ▁remains ▁of ▁semi - sub ter rane an ▁houses ▁built ▁into ▁the ▁beach ▁rid ges . ▁ ▁The ▁oldest ▁main land ▁sites ▁such ▁as ▁Battle ▁Rock , ▁Rab bit ▁Mountain ▁and ▁the ▁Lower ▁Ben ch ▁date ▁to ▁the ▁Pale o - Ar ctic ▁Trad ition , ▁about ▁ 1 0 , 0 0 0 ▁to ▁ 7 , 0 0 0 ▁years ▁before ▁present . ▁Similar ▁materials ▁have ▁been ▁recovered ▁in ▁the ▁Tra il ▁Creek ▁c aves ▁of ▁Ber ing ▁Land ▁Bridge ▁National ▁Pres erve ▁on ▁the ▁S ew ard ▁Pen ins ula . ▁The ▁Pal is ades ▁site ▁has ▁yield ed ▁materials ▁from ▁the ▁Northern ▁Arch a ic ▁period ▁d ating ▁to ▁about ▁ 6 , 0 0 0 ▁years ▁before ▁the ▁present . ▁Later ▁periods ▁described ▁in ▁the ▁region ▁include ▁the ▁Ar ctic ▁Small ▁Tool ▁tradition ▁and ▁the ▁Northern ▁Mar itime ▁tradition . ▁The ▁western ▁Th ule ▁culture , ▁which ▁used ▁dogs ▁and ▁se al ▁oil ▁extended ▁from ▁ 9 5 0 ▁AD ▁to ▁ 1 4 0 0 , ▁and ▁was ▁succeeded ▁by ▁the ▁Kot z eb ue ▁culture ▁from ▁about