See Joe’s number 5. Not sure where Joe got the tribal names for this, but they are in an area from the Rift Valley area of Kenya, to Namibia.
Rift Valley = Sum Dim Gorge, which is almost as good as gorging on dim sum.
Come on, Joe: out with it! Where’d you get the tie of SDG to those tribes?
From my primary interest in geology/mineralogy. I would have gone with Silicaceous Decomposed Granite.