Jour. Sci., XXIX, 1910. 



Map showing the Shinumo area (within double ruled lines) and distribution of Grand Canyon and Vishnu Series. From the Kaibab and Echo Cliffs topo- 

 graphic sheets, TJ. S. G. S. Contour interval, 250 ft. Scale about 5£ miles per inch. 



Faults, . Gband Canyon Series : Chuar Group, cross hatched. Unkar Group, solid black ; I, Type area described by Walcott ; II, Ottoman 



ar ea ; III, Bright Angel area ; IV, Hindu area ; V, Shinumo area ; VI, Tapeats area. Vishnu Series, x x x x. 



