416 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 19 3 2 



in an hourglass, mark off both the falling waters of the lake and 

 the advancing desiccation of North Africa. This piece of research 

 has thus, for the first time, disclosed the date of the desiccation 

 which created the Sahara Desert. This date is not in terms of years, 

 but in terms of human culture. It was in the middle of this Old 

 Stone Age commonly called Paleolithic, when the lake was still at 

 a level far above the sea, that the desiccation of North Africa began. 

 Such a tremendous change completely transformed the life of man 

 on the North African Plateau, and the discovery that Paleolithic 

 man was exposed to this change is one of epoch-making importance. 

 Thus we learn that while Paleolithic man was exposed to the advance 

 of the ice and the rigors of the Ice Age on the north side of the 

 Mediterranean, on the south side he was exposed to the desiccation 

 that transformed his fertile plateau home into the present Sahara 

 Desert. What was to be the result? 



DESICCATION OF NORTH AFRICA AND THE RISE OF MAN 



Before the desiccation set in, the entire North African Plateau 

 was without doubt plentifully watered and was inhabited by the 

 earliest hunters whom we know on the African Continent. The evi- 

 dences of their presence are distributed far across the Sahara from 

 the Nile to Morocco, in remote and inaccessible desert regions which 

 no hunter, however daring, would now venture to visit with any 

 hope of returning alive across the waterless waste. With the ad- 

 vance of the desiccation these hunters were forced to take refuge in 

 the Nile Valley, where there was plentiful water. The animals 

 which they had been commonly pursuing on the plateau probably 

 preceded them in great numbers to the bottom of the valley. This 

 close association of the hunter with the animals he pursued, due 

 directly to the desiccation which drove them both into the Nile 

 Valley, was without any doubt one of the influences which brought 

 about the domestication of animals. In a situation otherwise com- 

 pletely desert, the plentiful water obtainable along the shores of 

 the Nile likewise contributed to the development of earliest agri- 

 culture, especially after the Egyptians invented the plow. The sur- 

 viving evidences left by these processes are buried deep under the 

 Nile alluvium, which has been deposited by the river during the 

 last 15,000 or 20,000 years and perhaps longer. In boring an arte- 

 sian well at the new Luxor headquarters of the Oriental Institute 

 the drill brought up pottery at a depth of 75 feet. 



On the basis of these two possessions, cattle-breeding and agricul- 

 ture, there arose in the Nile Valley the earliest known social and 

 governmental structure — the earliest organized nation of several mil- 

 lion souls — a government, the emergence of which was itself the 



