- ri , ▁D ong sam - d ong , ▁and ▁Ga - do ▁Island ▁indicates ▁that ▁shell fish ▁were ▁explo ited , ▁but ▁many ▁arch ae olog ists ▁maintain ▁that ▁shell m idd ens ▁( or ▁shell m ound ▁sites ) ▁did ▁not ▁appear ▁until ▁the ▁latter ▁Early ▁Je ul mun . ▁ ▁Middle ▁Je ul mun ▁Ch oe ▁and ▁B ale ▁estimate ▁that ▁at ▁least ▁ 1 4 ▁Middle ▁Je ul mun ▁period ▁( c . ▁ 3 5 0 0 - 2 0 0 0 ▁BC ) ▁sites ▁have ▁yield ed ▁evidence ▁of ▁cultiv ation ▁in ▁the ▁form ▁of ▁carbon ized ▁plant ▁remains ▁and ▁agricult ural ▁stone ▁tools . ▁For ▁example , ▁C raw ford ▁and ▁Lee , ▁using ▁A MS ▁d ating ▁techniques , ▁directly ▁dated ▁a ▁domestic ated ▁fo xt ail ▁mil let ▁( Set aria ▁ital ica ▁s sp . ▁ital ica ) ▁seed ▁from ▁the ▁D ong sam - d ong ▁Sh ell m idden ▁site ▁to ▁the ▁Middle ▁Je ul mun . ▁Another ▁example ▁of ▁Middle ▁Je ul mun ▁cultiv ation ▁is ▁found ▁at ▁J it am - ri ▁( Ch it am - ni ) ▁in ▁North ▁Korea . ▁A ▁pit - house ▁at ▁J it am - ri ▁yield ed ▁several ▁hundred ▁gr ams ▁of ▁some ▁carbon ized ▁cult igen ▁that ▁North ▁Korean ▁arch ae olog ists ▁state ▁is ▁mil let . ▁However , ▁not ▁all ▁arch ae olog ists ▁accept ▁the ▁gra ins ▁as ▁domestic ated ▁mil let ▁because ▁it ▁was ▁gathered