Section A. 



a Yellowstone Kiver. i!) Silurian strata. c Cinnabar Mountain. d Cretaceous strata, 



e Crumpled strata. / Slope of Electric Peak. jfMetamorphic rocks (?). h Fragmentary volcanic rocks. 



Section B. 



a Tellowstone River. 6 Vertical Creta. shales, c Tufaceous marls, d Volcanic conglomerates, 

 e Sheets of basalt. /Metamorpbic rocks. 



detuli 



Section C. 



a Yellowstone, Kivcr. 6 Vertical slialcs. n Tufaceous marls. </ (longlomoratoa. 



eintnuled basalts. /Yellow and white sandstone, f/ Sheet of l)asalt. h Mctamorphic rocks 



Plate II. — CJ(!()l()>;v of Ycllow.stone Vall(!y. 



