PREGLACIAL MOINGONA RIVER 



555 



Old Moingona channel presents great umforuiity. Where the 

 channel traverses the water-shed between the Mississippi and 

 Missouri drainage systems the bottom of this channel is more 

 than 500 feet down. GTeneral hypsometric figures are given in 

 the subjoined Table I. The remarkably close agreement of the 

 bed-rock levels as calculated in three distinct and independent 

 ways is presented in Table II. 



GENERAL HYPSOMETRIC TABLE. 



Stations. 



^ o 5 



to 73 



H o O 



■3 qj +-> 

 a C ""' 



S.2 



Des Moines . . , 



P(Try 



Jefferson 



Aubaim 



Schaller ...... 



Kolstein , 



Correctionville 

 Sioux City . . 



34 

 20 

 32 

 28 

 14 

 14 

 36 



970 

 975 

 lOSO 

 1250 

 1390 

 1440 

 1300 

 1350 



300 

 250 



270 

 400 

 500 

 50O 

 340 

 300 



IL TABLE OP GRADIENT VALUES. 



Stations. 







5 *3 





Des Moines . . 



Perry 



Jefferson 



Auburn 



Schaller 



Kolstein 



Correctionville 

 Sioux City . . . 



34 

 20 

 32 

 28 

 14 

 14 

 36 



675 



725 

 780 

 850 

 890 

 940 

 960 

 1050 



675 

 745 

 795 

 845 

 LjO 

 920 

 970 

 1040 



675 

 745 

 785 

 850 

 905 

 935 

 970 

 1050 



There is another deep drift-filled, channel which branches off 

 from the one already mentioned at about where the town of 

 Perry stands, and which reaches the Missouri river valley at 

 Onawa. This may be the hypothetical stream which Prof. Todd'' 

 calls the Old Niobrara river. Whether the present Niobrara 



^Science, N. S., Vol. XXXIX, p. 263, 1914. 



