U. S. GlOGRAPHICAl AP GEOLOGICAL SURVEY OF THE ROCKY MOUNTAIN REGION. 



J. "W. POWELti, IliT CHARG-K. 



PRELIMIKARY REPORT 



PALEONTOLOGY of the BLACK HILLS, 



R. :p. ts^heitfield. 



-CONTAINING DESCRIPTIONS OF NEW SPECIES OF FOSSILS FROM THE 



POTSDAM, JURASSIC, AND CRETACEOUS FORMATIONS 



OF THE BLACK HILLS OF DAKOTA. 





WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 

 July, 1877. 



