TITLES AND ABSTRACTS OP PAPERS 85 



were extensive fluvial deposits of glacial age at Stoneliam and Clarendon. 

 The only way in which the current could thus have been deflected at that 

 elevation would be by a temporary ice obstruction below Warren. From 

 numerous considerations, it is evident that this obstruction was in the early 

 part of the Glacial epoch, thus throwing doubt on the distance of the col that 

 had to be eroded at Thompsons and emphasizing our conception of the extent 

 of preglacial erosion in this region. 



Presented by title in the absence of the author. 



PREGLACIAL MIAMI AND KENTUCKY RIVER8 

 BY N. M. FENNEMAN 



iAbstract) 



It is generally agreed that the preglacial Ohio flowed north of Cincinnati 

 to near Hamilton, Ohio (20 miles), and commonly supposed that it flowed 

 thence west and south to the present mouth of the Miami and from there on 

 had its present course. This has been disputed by Girard Fowke, who believes 

 that the preglacial Ohio flowed north from Cincinnati along the line of the 

 Miami (reversed). He depicts Kentucky River as continuing from its present 

 mouth along the line of the Ohio and Miami rivers (reversed) to near Hamil- 

 ton, Ohio, there joining the stream mentioned. The paper here presented 

 takes up the evidences concerning these three rivers under the following 

 heads: (1) The depth of the rock-floor at various places. (2) The width and 

 apparent age of the valleys at different points. (3) The angles at which 

 tributaries join their mains. (4) Asymmetrical form of divides as indicating 

 recent drainage changes. The conclusion is reached that the preglacial 

 Ohio flowed west from Hamilton, Ohio, instead of continuing northward, but 

 that the present Ohio trough at Madison, Indiana, is the result of recent 

 drainage changes. 



Presented in abstract from manuscript. 



Discussion 



Mr. I^ANK Leverett suggested that the asymmetry near Madison is prob- 

 ably due to the Muscatatuck drainage being in part postglacial. The narrow- 

 ness near Madison is at a place where the bluffs contain a much thicker bed 

 of resistant limestone than at narrows near Cincinnati. It may not be neces- 

 sary, therefore, to assume an old col to occur there. 



Professor Fenneman replied to Mr. Leverett: In regard to the assumption 

 that the rock-floor of the Ohio declines in altitude westward from the mouth 

 of the Kentucky. There has been much drilling in the channel at Madison on 

 account of the prospective dam and locks. Such borings have not revealed a 

 rock trough as low as that known at the mouth of the Kentucky. The argu- 

 ment based on the narrowness of the valley at Madison is made stronger by a 

 consideration of the undissected character of the adjacent uplands. This 

 tends to confirm the conclusion that the Ohio trough at that point is recent, 



