BULL. GEOL. SOC. AM. 



VOL. 14, 1902. PL. 43 



FniUKE 1. — Orenda Mesa 

 View from north, with cones of Zirivel mesa in background 



Bm^^^ 





Figure 2.— Black Rock Mesa 



FiGLUE 2. — Steamboat Mesa 



View from south with a ridge of sedimentary shale on the left, over which are drifting the sand glaciers to form 



dunes at the foot and to the east 



ORENDA, BLACKROCK, AND STEAMBOAT MESAS 



