Diamondiferous kimberlites (2.1 to 2.3 b.y. old) in west Africa are suggested as the source for alluvial diamonds found in association with the Rosebel Formation of Surinam (older than 1.8 b.y.). Current direction data from the lower Roraima group continental rocks (1.6 b.y. old) of Venezuela and Guyana indicate a source in Surinam for the sediment in the Roraima group. The abundant alluvial diamonds occurring with Roraima group strata may have a source in the Rosebel Formation in Surinam.