870 THE BOTTOM OF TEE SEA- 



The outward growth of the heads of deltas is 

 proved by many facts, but none are so striking as 

 those which concern the delta of the Nile. At one 

 time this river flowed into the sea through seven 

 branches, of which there were three principal ones. 

 Of these branches two only now remain — those of 

 Rosetta and Damietta. The exterior branches (the 

 Canopus and the Pelusiac) are filled up, and the 

 head of the delta, which was at one time under 

 the parallel of Heliopolis, is now about seven miles 

 nearer the sea. 



In all deltas the relative importance of the various 

 branches of the river is constantly changing. In the 

 time of the Etruscans the course of the Po was the 

 Po-di-Primaro, but now the principal branch is 

 farther north. 



The head of the delta of the Ehone is at Aries. 

 The western branch, now called the Little Khone, 

 was at one time the more important. It was itself 

 successor to a still more western branch, now dried 

 up. The principal course, at the present time, divides 

 into several branches before falling into the sea ; 

 one of these will, in course of time, alone remain, 

 as the others will gradually be filled up. 



