272 THE BEAUTIES OF NATURE CHAP. 



are continually changing their beds. Their 

 courses at first sight seem to follow no rule, 

 but, as it is termed, from a celebrated river 

 of Asia Minor, to " meander " along without 

 aim or object, though in fact they follow 

 very definite laws. 



Finally, when the river at length reaches 

 the sea, it in many cases spreads out in the 

 form of a fan, forming a very flat cone or 

 " delta," as it is called, from the Greek capi- 

 tal A, a name first applied to that of the 

 Nile, and afterwards extended to other rivers. 

 This is due to the same cause, and resembles, 

 except in size, the comparatively minute 

 cones of mountain streams. 



Fig. 35 represents the delta of the Po, and 

 it will be observed that Adria, once a great 

 port, and from which the Adriatic was named, 

 is now more than 20 miles from the sea. 

 Perhaps the most remarkable case is that of 

 the Mississippi (Fig. 36), the mouths of which 

 project into the sea like a hand, or like the 

 petals of a flower.. For miles the mud is too 

 soft to support trees, but is covered by sedges 

 (Miegea) ; the banks of mud gradually be- 



