120 THE UNIVERSITY OF OKLAHOMA 



checked by the large quantities of sand with which its channel is 

 choked. During a considerable part of the year the stream bed is 

 dry, all of the water moving slowly through the sand and hence 

 poAverless to erode or transport clastic materials while even in 

 flood the transportation of large quantities of sand then in suspen- 

 sion must consume much of the stream's energy and reduce its cut- 

 ting power. The fact that Little River, a tributary of the South 

 Canadian, which is not sand choked, has been able to reduce its 

 bed and much of its basin lower than the bed of the South Canadian 

 in Eastern Cleveland and Pottawatomie counties supports the view 

 that the sand choked character, particularly of the South Canadian, 

 has been an important factor in its inability to degrade its basin. 

 This sand not only retards dov/nward cutting of the Canadian 

 but also of its northern tributaries which are choked by sand blown 

 from the stream bed by the south winds. Much of this sand must 

 be removed by erosion before the streams can erode the underlying 

 residual materials. This appears to be an important secondary fac- 

 tor in determining the location of the Cimarron-North Canadian 

 divide. That the sand choked condition is of secondary, rather than 

 primary, importance in the control of erosion appears ■ evident, 

 however, from the fact that the Cimarron, like the South Canadian, 

 has a sand choked channel. 



XXIV. SOME OBSERVATIONS ON THE SOUTH 



CANADIAN RIVER NEAR NORMAN 



O. F. Evans 



From the Department o£ Geology of the University of Oklahoma, 



The laws of stream action have been worked out mostly from 

 the study of streams of the humid regions. The streams of the 

 arid and semi-arid regions have been given less attention and it 

 is quite common when such streams do not conform to the usual 

 humid type to consider thern as abnormal. However, the intermit- 

 tent stream is just as normal a type for the dry regions as the per- 

 manant stream is for the humid regions. While the same laAVS 

 of stream action hold for both types of streams yet the conditions 

 of work are so different in the two cases that an attempt to inter- 

 pret the phenomena of the streams of the arid districts by direct de- 

 ductions resulting from the study of streams of the humid regions 

 is apt to lead to erroneous conclusions. This paper is for the most 

 part a result of observations made in the bed and valley of the 



tSnider L. C. Bull. 27 Okla. Geol. Survey, P80, 1917. 



