EVIDENCE FEOM SOUTH DAKOTA 



477 



From these facts it will be readily seen that the principal relations of 

 the Missouri Eiver to the ice-sheet would be very similar to those in 

 Xorth Dakota. The principal difference would be that the ice extended 



1 



MAP 5HOW1N6 



THE PROBABLE HISTORT - 



or TME 



FDRMM10N°Vhe:^MIS50URI RIVER 

 50UTh"*DAKOTA 



acTooo. 192 

 EXPLANATIONS 

 Limit o( the glacial drift 

 Edqe of maximum ice sheetv v v*. 

 Morqin of oncient lakes ■ • 



Moraines 



PRE -WISCONSIN 

 WISCONSIN 



Altamont 



Gory 



Ancient Channels 



TERTIARY ^ 



PLEISTOCENE , . . 



Altitude, feet obove sea levelEOOQ 



1 .< 



2 .■ 



Figure 2. — Map of South Dakota 

 Showing probable history of the formation of the Missouri River in South Dakota. 



so far south that it did not reach its maximum extent so soon, and the 

 moraines formed would consequently be smaller and less continuous. 



For our purpose, it will not be necessary to present all the evidence 

 which might be stated. We will limit our discussion to two or three of 

 the more decisive points. 



