THE OHIO VALLEY IN SOUTHERN INDIANA 26 1 



The region in the interior, in all the triangular hill land, and 

 for a short distance north of the southern boundary of northern 

 hill land is covered with typical interstream loess. 



It follows in all of its details the characteristics of loess as 

 given by Salisbury. 1 It is best developed along the hills border- 

 ing stream channels, where it has the peculiar yellow or yellow- 

 ish buff loess color. Where exposed it weathers into perpen- 

 dicular banks. As it recedes from the stream channels it becomes 

 thinner and less characteristic. This change in thickness is 

 accompanied by a change in color, so that in the interstream 

 areas it so closely simulates residuary earth that it is impossible 

 to tell where one begins and the other ends. In parts of the 

 deposit, loess-kindchen are very numerous. They are of the 

 same type as those described by Call in Arkansas, 2 which, accord- 

 ing to his statement, differs from the typical northern loess- 

 kindchen in being solid. Limonite tubes and concretions and 

 immense numbers of very small land shells occur in some 

 deposits. 



The change from typical bluff loess to interstream loess is 

 noticeable in passing northward from the terrace in Pigeon 

 Plain. This peculiarity is of much assistance in working out 

 the origin of the terrace. 



The thickness of the loess along the border hills will average 

 about 20 feet. The highest elevation of the loess above the 

 plain is at Rockport, where it rises 110 feet. It was seen at 

 places on the " Knobs " at heights of about 100 feet. In nearly 

 all of the region it extends down to the level of the plains, and 

 much of the plains is made of redeposited loess. 



Along the eastern shores of Pigeon Plain this loess is inter- 

 laminated with a grayish sand in its lower portions. Along the 

 edge of the hills, and parallel with them, are many lenticular 

 sand hills ranging from 10 to 30 feet high. 



1 Ark. Geol. Survey, 1889, Vol. IT, "On the Relationship of the Pleistocene to 

 pre-Pleistocene formations of Cowley's Ridge," pp. 226-228. 



2 Ark. Geol. Survey, 1889, Vol. II, "Cowley's Ridge," by R. Ellsworth Call, 

 p. 38. 



