BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 13 pp. 27-40, pl. 3 January, 28 1902 



HYDROGRAPHIC HISTORY OF SOUTH DAKOTA 



BY J. E. TODD 



{Read before the Society August 27 ,1901) 

 CONTENTS 



Page 



Introduction 27 



Orogenic movements before the Pliocene 27 



Movements in the Pliocene 30 



Outlining of existing streams 30 



Persistent eastward drainage 30 



Beheading of streams farther south by the Cheyenne 31 



The ancient Minnechadusa 32 



In the early Pleistocene 33 



During the later Pleistocene 36 



Formation of the Missouri 36 



Displacement of the Niobrara. 38 



Diversion of the Big Sioux 38 



Peripheral and interlobular streams 39 



Introduction 



This paper combines several conclusions which the writer has pub- 

 lished elsewhere during the last decade, together with a few that are 

 here presented for the first time, and is an attempt to set them forth as 

 a consistent whole. In order to present a connected story, a few tenta- 

 tive conclusions and even mere guesses are introduced, but are distinctly 

 marked as such. Nearly all the streams mentioned have been more or 

 less personally examined. 



Orogenic Movements before the Pliocene 



In the later Archean or pre-Cambrian there w r ere evidently upheavals 

 at both ends of the state ; in the center of the Black hills and on the east 

 an extension of land from Minnesota between Dell rapids and Sioux 

 falls westward to the James river. 



Of the early Paleozoic little need be said, except that there was evi- 

 dently land in or near the Black hills, as is proved by the occurrence of 



V— Bum,. Geoi,. Soc. Am., Vol. 13, 1901 (27) 



