ne Ohio Naturalist, 



PUBLISHED BY 



The Biological Club of the Ohio State Uni'versity. 



Volume VIII. NOVEMBER. 1907. No. 1 



TABLE OF CONTENTS. 



Moody— Aggradation and Degradation of Valleys 191 



Morse— Contribution to the Life History of Cornns Florida . 197 



Williamson— Addition to List of Dragonflies of Canada 1204 



ScHAFFNER— Check List of Ohio Shrnbs 2C5 



Sim— The Chestnut-sided Warbler Nesting at Jefferson, Ashtabula Co., Ohio 209 



AGGRADATION AND DEGRADATION OF VALLEYS. 



A. E. Moooy. 



It is the purpose of this paper to show what a river can do 

 toward filhng and degrading its valley, to discuss the conditions 

 favorable to such work, and to briefly describe the resulting 

 land forms. The paper is based on an experiment which was 

 conducted at Ohio State University during the Winter of 1907 

 as a part of the work in Geology 21 — a course in advanced 

 physiography.^ 



A watertight box, eighteen feet long, two feet wide and six- 

 teen inches deep, was constructed; and then with weak cement 

 a mature valley was built in the box. The valley walls rose on 

 the sides of the box about five inches, and in the center the 

 construction was about one inch deep. Fig. 1. Spurs alter- 

 nately entered the valley from opposite sides. Fig. 2. The 

 cement covered the entire bottom of the box except about one 

 and one-half feet of the lower end which was left open for a 

 catchment basin, where delta formation was studied. The 

 upper end of the cement valley was covered with a pile of fire 

 clay upon which played a fine spray. 



At the lower end of the box was an elevated plug perforated 

 so as to let out the water above a certain height. This outlet 

 could be adjusted by changing the length of the plug, so that the 

 lake of accumulated water could be given any desired depth. 



A jack screw placed under the box about thirteen feet from 

 the mouth of the stream permitted regulating the slope of the 

 valley. Ordinary three-quarter inch rubber hose and a garden 

 nozzle connected with the city water pipes furnished the spray. 

 With varying city pressure frequent adjustment of the nozzle 

 was necessary to keep a fairly uniform stream. 



1 The author desires to thank Dr. Hubbard, under whom the course was taken, for 

 suggestions and criticisms both in the laboratory work and in the preparation of this report. 



