SMITHSONIAN MISCELLANEOUS COLLECTIONS 





^\ ^ - ^'' 



Unconformable contact on line (Arc) between Archean (/" = \'shnu series) and Cambrian ('/-TJl 



lorms terraced slope, and in turn is overlain bv Cambrian Muav limesione (.17) and by cliffs of grea |l 



Isis rests on Carboniferous sandstone. , 



Locality: North side of Grand Canyon of the Colorado River, Arizona, below Bright -Angel Canyon. || 



Ihis photograph and also plates 41, 42, and 43 taken by Norman \V. Carkhuff, chief photographer i 



Lettering on pla'es 40-43- t arbomferoiis : A' = Kaibab limestone; C' = Cocunino sandstone; Ssh'l 



Muav limestone; B.-^ = liright .Angel shale: r=Tapeats sandstone. Algonkian : f» = Unkar series. '' 



unconformity between .Algonkian and Cambrian. 



