▁are ▁the ▁expression ▁of ▁unique ▁social ▁and ▁economic ▁( sub s istence ) ▁solutions ▁to ▁environmental ▁and ▁dem ographic ▁challeng es ▁that ▁pre colon ial ▁San ▁h unter - g ather ers ▁faced ▁between ▁ 3 0 0 0 ▁and ▁ 2 0 0 0 ▁years ▁before ▁present ▁( B P ). ▁M TM ▁is ▁at ▁least ▁ ▁long ▁and ▁ ▁wide ▁and ▁has ▁a ▁depth ▁that ▁var ies ▁between ▁. ▁It ▁dates ▁to ▁between ▁ 9 8 0 ▁and ▁ 2 8 0 0 ▁B P , ▁however , ▁much ▁of ▁this ▁occup ational ▁sequence ▁dates ▁to ▁between ▁ 2 1 0 0 ▁and ▁ 2 5 0 0 ▁B P . ▁For ▁this ▁reason , ▁M TM ▁is ▁singular ▁among ▁meg am idd ens ▁in ▁that ▁it ▁offers ▁the ▁best ▁chron ological ▁resolution ▁( gre at est ▁volume ▁for ▁short est ▁time ) ▁for ▁the ▁later ▁part ▁of ▁this ▁unique ▁period ▁of ▁the ▁pre colon ial ▁history ▁of ▁South ▁Africa . ▁ ▁Meg am idd ens ▁ ▁Meg am idd ens ▁are ▁large ▁shell ▁m idd ens ▁that ▁are ▁found ▁along ▁the ▁sh or eline ▁of ▁the ▁West ▁Coast ▁and ▁consist ▁of ▁large ▁m ounds ▁of ▁shell s ▁( most ly ▁from ▁muss els , ▁along ▁with ▁bar n acles , ▁wh el ks , ▁lim p ets , ▁those ▁of ▁tort o ises , ▁and ▁fish ▁and ▁bird ▁b ones ). ▁The ▁meg am idd ens ▁were ▁created ▁over ▁a ▁ 1 , 2 0 0 - year ▁period ,