LITHOLOGY OF THE WHITE RIVER SEDIMENTS. 



Investigation aided by a grant from the Marsh fund of the National 

 Academy of Sciences. 



By HAROLD R. WANLESS. 

 (Plates IX. and X.) 



(Read April 22, 1922.') 



PAGE 



I. Introduction 184 



II. Generalized Section 185 



III. Method of Investigation 190 



IV. Types of Sediment 191 



The Channel Sandstones 192 



The Fresh-water Limestones 194 



The Caliche Nodular Layers 195 



The Volcanic Ash Beds 197 



The Clay Beds 198 



V. Evidence from Shapes of Sand Grains 199 



VI. Evidence of Ground Water Circulation 201 



VII. Conclusions drawn from the Lithogenetic Evidence 202 



I. Introduction. 



Since 1847, when the first White River fossil was described by 

 Dr. Joseph Leidy, the abundant and varied fauna of this series, as 

 exposed in the Big Badlands of South Dakota, has made it a center 

 of interest for paleontologists and collectors. During the field sea- 

 sons of 1920 and 1921 the writer has worked in this area with Pro- 

 fessor W. J. Sinclair with the object of tracing the detailed faunal 

 changes and determining, from the lithology of the beds, the condi- 

 tions of sedimentation through the successive formations which make 

 up the White River series. The work has been carried on in the Big 

 Badlands south and southwest of the town of Scenic in Pennington 

 County, and along the Wall of the Badlands north of Interior in 

 Jackson County. 



The earliest investigators assumed that most of the Tertiary 

 mammal-bearing beds of the west were lake deposits, and that the 

 excellent preservation of the skulls and skeletons they afforded was 

 due to protection by water from subaerial weathering and disintegra- 



