▁where ▁humans ▁dwell . ▁The ▁ced ar ▁tree ▁or ▁the ▁strip ed - center - pole ▁is ▁often ▁found ▁on ▁eng ra ved ▁con ch ▁shell ▁g or gets , ▁with ▁human ▁or ▁animal ▁figures ▁position ed ▁on ▁either ▁side . ▁The ▁concept ▁of ▁an ▁axis ▁m und i ▁— ▁the ▁point ▁where ▁different ▁cos mic ▁domains ▁conver ge ▁— ▁is ▁found ▁in ▁many ▁cult ures ▁around ▁the ▁world . ▁It ▁is ▁frequently ▁represented ▁as ▁a ▁tree ▁( including ▁the ▁Tree ▁of ▁Life ), ▁since ▁trees ▁pass ▁through ▁the ▁surface ▁of ▁the ▁earth ▁and ▁ ▁connect ▁the ▁sub sur face ▁and ▁the ▁sky . ▁The ▁fact ▁that ▁the ▁Great ▁Mort u ary ▁at ▁S pi ro ▁was ▁built ▁with ▁ced ar ▁( or ▁ced ar ▁el m ) ▁posts ▁suggests ▁that ▁the ▁bur ial ▁chamber ▁was ▁meant ▁to ▁be ▁a ▁point ▁of ▁departure ▁from ▁one ▁spiritual ▁domain ▁to ▁another , ▁as ▁ced ar ▁was ▁a ▁sacred ▁wood . ▁ ▁Arch ae olog ists ▁found ▁that ▁one ▁of ▁the ▁con ch ▁shell ▁cu ps ▁from ▁Craig ▁M ound ▁had ▁a ▁black ▁resid ue ▁in ▁the ▁bottom . ▁This ▁suggests ▁that ▁the ▁S pi ro ▁people ▁may ▁have ▁pract iced ▁a ▁version ▁of ▁the ▁Black ▁Dr ink ▁Cer em ony , ▁a ▁pur ification ▁rit ual ▁that ▁was ▁also ▁performed ▁in ▁historic ▁times ▁by ▁their ▁descend ants ▁- ▁the ▁S out he astern ▁tribes . ▁Part icip ants ▁d rank ▁a ▁tea ▁made ▁from ▁the ▁Y au pon ▁Hol ly ▁from ▁con ch ▁shell ▁cu