SURFACE FEATURES. 



41 



Slopes of the Principal Rivers of Iowa — Continued. 



NAMES. 



E. Nishnabotany. 



W. Nishnabotany 



Boyer 



Little Sioux 



Little Sioux 



Big Sioux 



Big Sioux 



Floyd 



PAKT OP COURSE. 



From C. R. I. and P. Railroad 



to the mouth 



From C. R. I. and P. Railroad 



to the mouth 



From Dennison to the mouth. 

 From Cherokee to SmithLmd, 

 From Smithlancltothe mouth 

 From N. W. corner of the 



State to Indian creek 



From Indian creek to the 



mouth 



From fork of Willow creek to 



the mouth 



SLOPE 

 PER MILE. 



AUTHORITY. 



2 ft. 5 in, 



2 ft. 



3 ft. 



2 ft. 

 Oft, 



3 ft. 

 lft. 

 3 ft 



8 in. 



3 in. 

 6 in. 



4 in. 



2 in. 

 4 in. 

 Oin. 



Railroad levels. 



Railroad levels. 

 Railroad levels. 

 Railroad levels. 

 Railroad levels. 



Approximate estimate. 



Approximate estimate. 



J. E. Aicsworth. 



The rivers of Iowa alone would furnish material for a 

 much more lengthy discussion than the limits of this report 

 will allow, but the most that can be done at the present time 

 is to give an outline of their general and peculiar characters, 

 confining remarks in reality more to the valleys than to the 

 the streams themselves. 



Notwithstanding the general flatness of the country through 

 which our rivers pass, the characters of their valleys are some- 

 what varied by the difference in the character of the forma- 

 tions out of which they have been eroded, and over which 

 their waters flow; and also by the depth to which the slope 

 of the surface from their sources to their mouths have re- 

 quired their erosion. The conditions being the same, the 

 character of the valleys and their streams would everywhere 

 be uniform, and there is consequently a great degree of uni- 

 formity among Iowa streams. This uniformity is due to the 

 depth and universal prevalence of the surface deposits more 

 than to any other cause. It is especially so in Western Iowa 

 where the stratified rocks are generally and deeply covered 

 by those deposits. 



In attempting to divide the rivers of Iowa into classes for 

 more convenient description, each class having certain charac- 

 teristics in common, no more natural division can be made 

 than that which separates the two drainage systems as before 

 described. 

 6 



