U. S. GEOLOGICAL SURVEY 



BULLETIN 612 PLATE XVII 



A, GREEN RIVER CITY, WYO., AS SEEN FROM CASTLE ROCK, 



Photograph furnished by Union Pacific Railroad Co, 



B. NATURAL MONUMENTS WEST OF CASTLE ROCK. 



Some of these monuments have assumed curious shapes, Uke the "teapot and cup," shown above. They are 



composed of the regularly laminated Green River shale capped by hard brown sandstone. 



