BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 26, pp. 217-230, PL. 9 JUNE 28, 1915 



OEIGIN OF THE RED BEDS OF WESTERN" WYOMING ^ 



BY E. B. BRANSON 



(Presented before the Society December 29, 19H) 



CONTENTS 



Page 



Introduction 217 



Historical 218 



Description of ttie Red Beds of western Wyoming 218 



Conditions of the upper Red Bed gypsum deposits 222 



Hypothesis for origin of gypsum deposits 223 



Statement of the hypothesis 223 



Topography of drainage area supplying water for the deposits 223 



Relation of run-off to precipitation 223 



Materials in solution in river waters 224 



Assumptions made in working out hypothesis 225 



( 'onditions not explained hy the hypothesis 22(5 



What became of the calcium carbonate? 226 



What became of the sodium chloride and other salts? 227 



Time, erosion, and purity 228 



General conclusion 228 



Summary 228 



Succession of events 229 



Age of the Red Beds 229 



TNTKOnUCTION 



After woi-kiiif;- on the Red Beds (Chngwater formation) of western 

 Wyomin<; for four summers, the writer is convinced that some recent 

 investifratoi'S are assigning their origin too largely to subaerial forces. 

 He has found proof of such origin in one member about 60 feet in thick- 

 ness, evidence of scolian origin in another member of about the same 

 thickness, and abundant indications of subaqueous origin for all of the 

 rest. 



The writer's investigations were made during the summers of 1904 and 

 1905, when he worked on the Rod Beds from about 20 miles south to 



' Manuscript r«»coivpd by tho Secretary of Ihe Oeologlcal Society February 8, 1915. 

 XVII— Bull. Giool. Soc. Am., Vou 26, 1914 (217) 



