▁and ▁visitors ▁al ike ▁were ▁in ▁fact ▁a ▁recent ▁development ▁in ▁Pre - Contact ▁Cham or ro ▁society . ▁The ▁lat te ▁stone ▁consists ▁of ▁a ▁head ▁and ▁a ▁base ▁sh aped ▁out ▁of ▁lim estone . ▁Like ▁the ▁E aster ▁Island ▁stat ues , ▁there ▁is ▁plenty ▁of ▁spec ulation ▁over ▁how ▁this ▁was ▁done ▁by ▁a ▁society ▁without ▁machines ▁or ▁metal , ▁but ▁the ▁generally ▁accepted ▁view ▁is ▁that ▁the ▁head ▁and ▁base ▁were ▁et ched ▁out ▁of ▁the ▁ground ▁by ▁sharp ▁ad zes ▁and ▁pick s ▁( poss ibly ▁with ▁the ▁use ▁of ▁fire ), ▁and ▁carried ▁to ▁the ▁assembly ▁area ▁by ▁an ▁elaborate ▁system ▁of ▁ro pes ▁and ▁logs . ▁The ▁lat te ▁stone ▁was ▁used ▁as ▁a ▁part ▁of ▁the ▁raised ▁foundation ▁for ▁a ▁mag al ah i ▁( m ata o ▁chief ) ▁house , ▁although ▁they ▁may ▁have ▁also ▁been ▁used ▁for ▁can oe ▁sh eds . ▁ ▁Arch ae olog ists ▁using ▁carbon - dating ▁have ▁broken ▁Pre - Contact ▁Gu am ▁( i . e . ▁Cham or ro ) ▁history ▁into ▁three ▁periods : ▁" Pre - Lat te " ▁( BC ▁ 2 0 0 0 ? ▁to ▁AD ▁ 1 ) ▁" Trans itional ▁Pre - Lat te " ▁( AD ▁ 1 ▁to ▁AD ▁ 1 0 0 0 ), ▁and ▁" Lat te " ▁( AD ▁ 1 0 0 0 ▁to ▁AD ▁ 1 5 2 1 ). ▁Arch ae ological ▁evidence ▁also ▁suggests ▁that ▁Cham or ro