Hildiid,
You have debunked exactly nothing. You've given a reference, but no link. The quote is talking about an argument over the expansion, not anything that was proven. Both the northern and southern divisions of the Eastern Cushites are from the Sudan. The northern division lasted so long because the Afar-Saho were already nomads at the time of the Kushitic states.
Here are the Eastern Cushites according to the Kenyans:
http://www.enzimuseum.org/peoples-cultu ... n-cushites
"The origin of the Galla (Oromo) is to be found in the highland region around Bali in South-Central Ethiopia and traditions are unanimous in confirming this. The centre of the Galla dispersal is traced around the region, which is currently the homeland of the Boran. Over the years the vital areas of Boran migrations and settlements were the homelands of Dirre and Liban, and the lowland region of Golbo and Wanyama stretching from the east of Lake Rudolf (Turkana) to Qaddaduma and beyond in the east. It also included Dadasha Waraba as the furthest out post of Boran settlement in the north-east directions, in the lower reaches of the Dawa and Ganale Gudda rivers."
If I am not mistaken, part of the Dawa is in Gedo, which would not be anywhere near Eritrea. The Lake and Omo-Tana region is where the Bulk of the Cushitic languages congregate. Eritrea is home to the Semitic languages and the corridor that splits the Cushitic in Ethiopia and along the Red Sea coast, so not a likely candidate just on the face of it.
I am glad to see you've got it down to 4000 years now, but you are going to have to do much better to "prove" anything. You also need to deal with this:
http://www.as.utexas.edu/~wheel/africa/ ... nga_01.htm
Namoratunga
"The cultural background of Namoratunga (somtimes rendered "Ng'amoritung'a," a spelling perhaps closer to the original language) lies shrouded in much mystery, as does its purpose. Evidence for the Namoratungan's cultural heritage is found in the rock art found at Namoratunga I. These petroglyphs closely resemble brands on livestock that the Turkana use. These cattle brands could have come from a common past as Lynch points out in his response to Robert Soper's challenging paper. The cattle brands seem to point to the fact that the Namoratungans probably were ancestors to the present-day Cushitic and Nilotic-speaking peoples.
The cattle burials at Namoratunga I are very interesting though because of the lack of explanation. Were these burials ritual sacrifices or did they see these cows as gods? There seems to be a cattle burial connection between Namoratunga and the Nabta area because Wendorf, a noted expert on Nabta, wrote a paper on cattle burials in the Sahara.
The most striking connection between Namoratunga II and the present day peoples is the connection with the Borana calendar of the modern-day Cushites. If Mark Lynch's astronomical alignments were right, then this would provide much evidence towards the Namoratungans being the ancestors of the present-day Cushites. The other interesting tie here is that the Borana calendar only works if precessed back to 300 BC. This date is very near the radiocarbon date for Namoratunga I. An unanswered question in all of this is why a calendar which does not work anymore is still being passed down. All of this seems to provide much evidence for the Namoratungans being the ancestors of the current day Cushites still living near Lake Turkana."
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The connections to the Sahara, Kush, the southeastern Cushites, the Oromo and the Samaale should be obvious. The date is 300BC, 300 years before the proto-Sam began their march north to the Ogaden plains.