HURRICANE FAULT IN SOUTHWESTERN UTAH 63 



section the fault followed the greatest of the folds, while in the 

 portion south of Toquerville it traversed nearly horizontal plateau 

 strata. These disturbances introduced the inter-fault cycle of 

 erosion — a long period of comparative quiet, during which the 

 outcrop-cliffs on the two sides of the fault receded northward at 

 different rates, and the whole country was reduced to a degree of 

 relief far less than the present. The southern region approached 

 peneplaination, while toward the north the surface rose into 

 graded mountainous hills separated by broad valleys. The close 

 of this period was heralded by aggradation in the main valleys, 

 and by extensive lava flows. In the second period of upheaval 

 came the uplift of the Plateau province, marked by a displace- 

 ment along the Hurricane and Grand Wash faults. The last 

 period, or Grand Canyon cycle, has seen the cutting of numerous 

 deep canj'ons and the stripping of large areas of soft strata ; but 

 its main work as a cycle of erosion is as yet only begun. 



Ellsworth Huntington. 



James Walter Goldthwait. 



