PIRATES IN THE MOUNTAINS 69 



The delta of the Yellow River, China, is said 

 to be three hundred and fifty miles across. 

 The delta of the Ganges is about the size of the 

 state of Pennsylvania. The delta of the Mis- 

 sissippi is about the size of Florida, but no one 

 knows how deep. At New Orleans, which is 

 built upon the older part of the delta, a log was 

 found in well drilling a thousand feet beneath 

 the surface. 



One mile every sixteen years is the rate which 

 the Mississippi is building out the delta filling 

 in the sea with the wash off land. The city of 

 Adra on the Po River, Italy, now is fourteen 

 miles from the sea. It formerly was at the 

 mouth of the river. In China generations ago 

 the city of Pu-tai was a seaport at the edge of 

 the ocean, but running water has built a large 

 delta beyond it and now it is forty-eight miles 

 from the sea. These deltas sink into the sea. 

 Perhaps it is their own weight that causes this 

 slow sinking. Beneath the sea, time, pressure, 

 and its own cement change delta material into 

 stone. 



