232 Camjyhell — Fractured Bowlders in Conglomerate. 



when exposed to the atmosphere, leaving only a mass of gravel 

 and bowlders. The material is all well rounded, and it seems 

 evident that it has been swept into its present position by 

 strong currents of water, presumably by surface streams. 



Bed of Cretaceous conglomerate on Ash Creek, Pinal County, Arizona. 

 Andesitic tuff matrix. Dip 70 degrees to left. Bowlders fractured. 



After the deposition of this material, the rocks were dis- 

 turbed by what seems to have been the upthrusting of huge 

 masses of igneous rocks, giving to the sedimentary beds the 

 form of an irregular basin. In some places the movement has 

 been quite severe, and the rocks are steeply upturned and 



