AN ECOLOGICAL STUDY OF DRY RUN, A TYPICAL 

 PRAIRIE STREAM 



/. THE FISHES 



E. LAURENCE PALMER 



Dry Run, a tributary of Cedar river in Black Hawk county, Iowa, 

 furnishes an excellent unit for studying the ecology of a prairie 

 stream. It is rather exceptional in that for a greater portion of the 

 year a natural barrier is formed where the stream flows underground 



for the last two miles of its course. 

 This study is concerned only with 

 the west branch which joins a 

 brook of similar size near the 

 grounds of the Cedar Valley Fair 

 Association. While this paper 

 deals only with a description of 

 the creek and the distribution of 

 its fish inhabitants, it is the plan 

 to submit subsequent articles 

 dealing with other forms found. 



The upper part of the west 

 branch of the stream follows quite 

 closely w^hat is known as "The 

 Diagonal Road," figure 10. After 

 passing the northern end of this 

 road, the stream bed continues on 

 in the same direction through the 

 Natural Science Park of the Iowa 

 State Teachers' College. The 

 stream is about five miles long 

 from the source to the "springs." 

 The upper three miles have water 

 throughout the year. The tilt of 

 the strata of earth beneath the 

 stream is contrary to the direction 

 of the current. This causes, in 

 part, the marked variation in the 



6oaoh»rB' Coll»g» 



Fio. 10. — Map sliowing course 

 of Dry Run for the upper three 

 miles. 



