28 GEOLOGY OF THE HIGH PLATEAUS. 



babs, for the two districts have a common history, so far as relates to tlieir 

 more recent structure. The individual faults overlap, and both districts 

 sympathized in the vertical movements. Indeed, the Hurricane and Eastern 

 Kaibab faults form structure lines of the first magnitude in both districts, 

 with no break in the continuity. The indications are unmistakable that the 

 upliftings of the Kaibabs and High Plateaus were sensibly synchronous 

 and formed one movement, and that any attempt to separate them would 

 be to ignore their proper relations. 



The westernmost of the series is the Grand Wash fault. It crosses the 

 Colorado at the lower end of the Grand Canon. Southward it curves 

 gradually in its trend, and at the farthest point to which it has been traced 

 its course is to the southeast. Northward from the river the curvature of 

 the trend is still preserved though much less distinct, and its course is 

 nearly due north. It runs out apparently about 35 miles from the river. 

 Its maximum displacement is about 5,500 feet, and the lifted side forms the 

 Sheavwits Plateau. 



Next in order comes the Hurricane fault. Its southern terminus south 

 of the Colorado is unknown. It ci'osses the river just west of Mounts 

 Trumbull and Logan, forming the Hurricane Ledge, and its course is nearly 

 north, with a very slight swerving to the eastward. At the Grand Canon 

 its displacement is about 1,800 feet, and this amount is maintained with 

 little variation for about 40 miles north of the canon. Here its throw (to 

 the west) rapidly increases. It becomes the western boundary of the great 

 Markiigunt uplift — the southwesternmost of the High Plateaus, and is at 

 the same time the boundary which sharply separates the Plateau Province 

 from the Great Basin. Continuing on past the Mormon town. Cedar, and just 

 before reaching Parowan, it suddenly swings eastnortheast, making almost 

 a sharp angle. Thereafter it swings slowly back towards the north until it 

 reaches the western flank of the Tushar, where its throw has much dimin- 

 ished. The precise point where it runs out is not known, since it is covered 

 by basaltic eruptions, but it is not seen beyond the middle of the western 

 flank of the Tushar. Its maximum throw is near Cedar, on the western 

 flank of the Markagunt, where it reaches on an average, along 20 miles of 

 its course, a displacement of about 5,000 feet. 



