414 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 2 



many gaps in our geological knowledge of this area of northeastern 

 Africa, but our prehistoric survey has been able to follow the suc- 

 cessive stages of the geological history of the Nile, notwithstanding 

 the unavoidable gaps. Back in Oligocene time, millions of years ago, 

 the river began as a colossal but meandering stream carrying north- 

 ward the drainage of all Northeast Africa across the North African 

 Plateau to the predecessor of the Mediterranean Sea. It transported 

 enormous masses of gravel, which now overlie vast areas of the North 

 African Plateau. Here and there lie scattered also silicified or 



Figure 1. — Map sbowiug the field operatiuus of the Orieutnl Institute iu the Near Ea«t 



petrified tree trunks as much as 70 feet long, brought down on the 

 waters of this mighty Oligocene river. There is no evidence of 

 man's presence along this earliest Nile. 



EARLIEST EVIDENCES OF MAN YET DISC0\"ERED IN THE NEAR EAST 



Somewhat east of its earliest course this drainage began to cut a 

 channel which finally deepened and expanded into the present Nile 

 Valley. As its volume diminished the shrinking river left on either 

 hand a series of terraces, in which our Prehistoric Survey has dis- 

 covered early implements of Stone Age man buried in the structure 

 of the terraces as in the river terraces of Europe. Along a section of 

 the ancient river bed now dry, and belonging to the early stages of 

 the Nile in its present valley, the survey discovered a stretch of over 

 60 miles of the early Nile bed some 60 feet in depth, and at the bot- 



