196 The Ohio Naturalist. [Vol. VIII, No. 1, 



It was noticed, as above stated, that the doubhng of the 

 volume more than doubled the power of the stream. If the 

 volume cotild have been doubled without increasing the velocitv, 

 undoubtedly the power would have been little more than 

 doubled, but this is probably impossible; and since increasing 

 velocity so greatly augments power, the marked increase is thus 

 explained. 



To test the influence of changes in slope, the steepness was 

 increased and decreased temporarily under various conditions. 

 The results may be summarized as follows: During the earlv 

 part of the experiment when the stream was constantly loaded 

 to its maximum capacity, decreasing the steepness checked the 

 velocity and power of the stream from the loading point to its 

 mouth, and hence reduced the rate of deposition because the 

 stream could not start as much waste as formerly, when its power 

 was greater, and manifestly could not drop as much either. 

 Under the same loaded conditions with abundance of waste to be 

 picked up at the source, steepening the slope increased deposition 

 instead of initiating erosion because the stream was able to pick 

 up more waste at the start and hence had more to drop along the 

 valley. These results are really not anomalous, but, when the 

 problem is thought out, quite expectable. No quantitative 

 tests were made but the general results as here stated were so 

 apparent that we believe the facts are exactly as stated above. 



When the stream was degrading dttring the latter part of the 

 experiment, a slight increase in slope increased the rate of 

 degradation and a similar decrease in steepness checked erosion, 

 while more reduction in slope stopped erosion almost completely. 



Inasmuch as such changes in slope do not enter into the 

 ordinary field problems of streams we mav consider the effects 

 of changes in volume of water and quantity of waste in their 

 general application without considering changes of slope. The 

 experiment was somewhat abnormal to nature in another 

 respect, for in nature waste is not usually fed into a stream, 

 absolutely as fast as the stream will pick it up regardless of 

 variations in the stream's power. In nature, supply of rock 

 waste varies with the volume of water. 



Resulting land forms. — The forms resulting from a river's 

 aggrading and subsequently degrading its course are mainly of 

 an ephemeral type. To begin with a constructional plain is 

 formed occupying the valley filled. This plain is composed 

 of loose, more or less systematically stratified materials which, 

 as a rule, do not have time to become much consolidated 

 or cemented before the stream changes its habit and proceeds to 

 send the waste, temporarily rested along the valley, on its 

 journey to the sea. Terraces are thus carved with their level, 

 often crescentic top plains and their steep, serrate, or cuspate, 



