Where was Robert Lee Manning buried

He served out of Camp Pendleton, Cal. and was killed at Iwo Jima 3-10-1945,He was a paratrooper and was highly decorated Marine.His son was 6 mos. old at that time and would really want to have this information. PLEASE, if you have information, it would be highly appreciated.
His Mother filed a claim for dependency allowance,after his death, but it is rather smeared.It looks like his rank was M.G. 1ST P.Bt1st Mar.Amp.Cps.