Were the Olmecs Black Africans?

"It is indisputable that in very ancient times the Negro race occupied our territory [Mexico]." -- Vicente Riva Palacio, historian, 1870

"In Aztec mythohistory, the Olmecs were known as ‘the people who lived in the direction of the rising sun’...." -- Victor W. Von Hagen, archaeologist, The Ancient Sun Kingdoms of the Americas, 1957

"Remember that, just like in Egypt, a great [Olmec] civilization flourished and then died. And then people forgot all about it. The pyramids lay under the sand, the sphinx lay under the sand, something stood there like enigmatic witnesses of a glorious past, but many people continued to live for centuries without recovering the majesty of that civilization, without being able to go back to their roots." -- Ivan Van Sertima, historian, 1976

"They didn't believe black Africa was capable of producing high civilization." -- Timothy Kendall, archaeologist, The Nile's Other Kingdom, September 15th 1997

Hayes, F.W., III, The African Presence in America Before Columbus, 1973

Van Sertima, I.A., African Presence in Early America, 1987

Barton, P.A., The Olmecs: An African Presence in Early America, Feb 2001

Barton P.A., Black Civilizations of Ancient America (Muu-Lan), Mexico (XI), 2001

Winters, C., Race and Identity: Ancient Relations Between Africans and Mexicans, 2005

UPDATE: Afro-Olmec cornrows.