276 



SCIENCE. 



[N. S. Vol. XX. No. 504. 



cutting may be overcome in part, in whole, 

 or may even be exceeded by the effect of 

 the westerlies on the surface of the stream. 

 If the river flowed north these two forces 

 would combine to produce an effect that 

 might be thought to be greatly in favor of 

 the argument for deflection. In reality it 

 would offer no better example than the 

 Mississippi with its present direction of 

 flow. In the former case the operation of 

 the force would be less visible, but the 

 proof of the existence of the force would 

 be no less clear. 



The best examples of deflection in these 

 latitudes must, therefore, be sought among 

 streams flowing neither north nor south, 

 but in the line of the winds — east or west. 

 The deflective tendency will, of course, be 

 as strong under the latter conditions as 

 under the former, while the effect of the 

 westerlies will be distributed over right- 

 handed and left-handed curves alike. 

 "When a larger number of measurements 

 of cutting on such streams have been made 

 and the wind effect and deflective tendency 



EiG. 2. The Cut-ofif at Vieksburg. 



evaluated, it may be seen that the Missis- 

 sippi offers as good proof of such tendency 

 as any river we can find. The resolution 

 of forces in such a manner as to produce 

 a negative effect is no less interesting than 

 the resolution of those same forces in pro- 



ducing a positive effect. A volcanic cone 

 gradually and continuously building in 

 mid-ocean at a rate which just counteracts 

 the attack of the sea does not impress the 

 geographer less than the loftier cones of 

 similar origin more favored by position and 

 climatic conditions. 



Attention is called to the fact that be- 

 tween Rosedale and Vieksburg there are 

 four cut-offs on the right and an equal 

 number on the left side. Between Vieks- 

 burg and Bayou Goula Bend there are five 

 on the right side and but one on the left, 

 and that at Vieksburg, the dividing point 

 between the two sections. This cut-off, as 

 shown in Fig. 2, seems to have been pos- 

 sible only because of the direct way in 

 which the river swings toward the bluffs 

 from its previously free course on the open 



Fig. 3. The Meander and Cut-offs at Natchez 



showing effects of Restraints exercised by 



Bluffs on tlie Right Side of the River. 



flood-plain. A bend having developed up- 

 valley from the general course of the 

 stream it was reasonably certain that the 

 river, with the bluffs holding in the current 

 on the left side, should at last pinch off 

 the lobe and produce a cut-off; while 

 farther down stream, where the general 

 course of the river is close to the bluffs, 

 cut-offs are just as certain to occur on the 

 right side. 



