THE PREGLACIAL DRAINAGE OF OHIO. Z6 



to the present level of the river so that the bold rock cliffs and 

 the numerous deep ravines present very picturesque scenery. 

 Below this col the valley gradually broadens again and the walls 

 become less precipitous as far down as Coolville, (plate IV). 

 Between Coolville and its mouth the river again passes through 

 a narrows. That the narrows at this point is the site of an old 

 col is not so evident as in the other cases farther up the river. 



CHARACTER OF THE FEDERAL CREEK VALLEY. 



A study of this valley was not included under the outline 

 planned for the work for the Academy, but it soon became evi- 

 dent, from the field work, that under one of the working hypoth- 

 eses it might prove to be in the line of discharge of the waters 

 of the Muskingum, so that its investigation became necessary. 

 The divide separating the waters of Federal Creek from those 

 of Wolf Creek and the Little Hocking was carefully examined 

 for an abandoned valley floor, but none was found. There are 

 some low cols in the divide which may possibly have been occu- 

 pied by water during some of the high water stages associated 

 with the drainage modifications. 



The valley of Federal Creek is rather deep and narrow in its 

 lower portion, but in the section around Amesville is much 

 broader. All the tributaries on the northern side occupy rather 

 broad valleys. The effects of the rejuvenescense which are so 

 marked a feature throughout most of the region are less apparent 

 in the Federal Creek basin than anywhere else in the entire 

 region. The data upon which rests the location of the old col 

 below Amesville are not as satisfactory as could be desired. 

 The location is made more from the necessities of the case than 

 from field observations. 



CHARACTERS AND DISTRIBUTION OF THE OLD VALLEY FLOORS. 



It is very evident that as soon as a 'river deserts any part of 

 its valley, the abandoned portion will develop at once into a 

 divide from which the waters will flow each way into the remain- 

 ing sections of the river. This will be especially true if from 

 any cause a river course is divided and one portion caused to 



