▁m ▁thick ▁and ▁composed ▁of ▁p um ice ▁sand stone ▁that ▁is ▁cross - bed ded ; ▁it ▁is ▁situated ▁in ▁the ▁southern ▁half ▁of ▁the ▁Bou ri ▁hor st ▁and ▁ ▁dated ▁to ▁ 1 ▁my a . ▁F oss ils ▁found ▁in ▁the ▁layer ▁suggest ▁open ▁grass land — some ▁ 3 7 7 ▁species ▁of ▁b ov ids ▁( including ▁three ▁new ▁species ▁and ▁two ▁new ▁gener a ); ▁and ▁water - margin ▁habit ats — species ▁of ▁Kob us ▁ant el ope ▁and ▁abund ant ▁Hi pp op ot am us . ▁Early ▁A che ule an ▁stone ▁tools ▁such ▁as ▁hand ▁axes ▁and ▁cle a vers ▁have ▁also ▁been ▁found ▁in ▁the ▁D aka ▁member , ▁as ▁well ▁as ▁evidence ▁of ▁but ch ery ▁processing ▁on ▁equ id , ▁b ov id ▁and ▁hi ppo ▁b ones . ▁ ▁H omo ▁ere ct us ▁foss ils ▁include ▁the ▁spec imen ▁BO U - VP - 2 / 6 6 , ▁or ▁the ▁D aka ▁sk ull , ▁an ▁incomplete ▁sk ull ▁that ▁had ▁an ▁end oc ran ial ▁capacity ▁of ▁ 9 9 5   cm 3 . ▁ ▁These ▁foss ils ▁( of ▁H . ▁ere ct us ) ▁are ▁important ▁to ▁the ▁current ▁debate ▁as ▁to ▁whether ▁Asian ▁and ▁African ▁H . ▁ere ct us ▁were ▁actually ▁different ▁human ▁species . ▁As f aw , ▁et ▁al . ▁( 2 0 0 2 ) ▁reports : ▁ 1 ) ▁that ▁these ▁foss ils ▁do ▁not ▁support