566 



APPENDIX. 



Generalized Section for the Black Hills. 1 



Names of Formations. 



O , 



-3 <u 



White River for- 

 mation. 



Laramie formation 



Fox Hills forma- 

 tion. 



g [ Pierre shale. 



Niobrara forma- 

 tion. 



Carlile formation. 



Greenhorn lime- 

 stone. 



Thickness 

 in Feet. 



L'OO 



2500 



250-500 

 1200 



225 



500-750 



50 



Characteristics. 



Porous, crumbling clay, with coarse sand- 

 stone and conglomerate; non-marine de- 

 posits, commonly classed as lacustrine. 



Massive sandstone and shale; mainly non- 

 marine. 



Sandstone and shale; marine. 



Dark gray; marine. 



Chalk and calcareous shale ; marine. 



Gray shales with thin sandstone, limestone, 

 and concretionary layers; marine. 



Graneros shale. 



Dakota sandstone 



Fuson formation. 



Minnewaste lime- 

 stone. 



Lakota formation 



Morrison shale. 



Unconformity -^- 

 Beulah shale. 



Unkpapa sand- 

 stone. 



Sundance forma- 

 tion. 



•£•§ I Spearfish forma- 

 h|[ tion. 



r^ f Minnekahta lime- 





stone. 



Opeche formation. 



900 



35-1 50 



30-100 



0-30 



200-350 



0-250 



60-400 



350-500 



30-50 



Impure, slabby; marine. 



Contains lenses of massive sandstone; marine. 



Massive, buff; non-marine, at least in part. 



Fine-grained sandstone, and massive shales; 

 white to purple; no fossils. 



Gray; no fossils. 



Massive buff sandstone, intercalated shale; 

 largely non-marine. Fossils cycads. 



Massive, and of gray, green, and maroon col- 

 ors; thin beds of sandstone. 



Pale grayish green; marine. 



Massive, white, purple, red, and buff; marine, 

 shallow-water deposits. 



Dark drab shales and buff sandstones; mas- 

 sive red sandstone at base; marine, shallow- 

 water deposits. 



Red sandy shales with gypsum-bed; salt lake 

 deposits. 



Thin-bedded, gray; marine. 



90-130 | Red slabby sandstone, and sandy shale ; marine. 



1 Darton, 21st Ann. Rep. U 

 mont folio, U. S. Geol. Surv. 

 Geol. Surv., pp. 178-181. 



S. Geol. Surv ., Part IV, pp. 503-504, and Darton and Smith, Edge- 

 Ordovician inserted from Jaggar, 21st Ann. Rept., Part III, U. S- 



