DAVIS: THE PLATEAU PROVINCE OF UTAH AND ARIZONA. 7 
Eocene, for the Eocene strata west of the fault seem to have been de- 
formed by an east-dipping monoclinal flexure as in Figure 2, before they 
were faulted; and a significant period of post-Eocene time must be 
allotted not only to the production of the flexure, but also to the re- 
arrangement of the deep-seated telluric forces, so that a fault with uplift 
on the east should succeed a flexure with uplift in the west. 
The existing condition of the Sevier fault is well shown between Sea- 
man’s Ranch on the Virgin and the group of ranches known as the 
Upper Kanab on the creek of that name. The road forks between these 
two settlements and crosses the fault at points about a mile apart. The 
upper white and red members of the Tertiary series here exposed west of 
the fault are submaturely dissected, so that the eastern border of the 
Markagunt plateau in this district shows open valleys branching among 
rounded hills, whose slopes often exhibit contouring ledges. Three small 
shallow “lakes”? or marshy meadows held back by fans from lateral 
ravines lie in the valley of the Virgin just west of the fault. The gentle 
eastward dip of the strata increases to about 10° near the lakes; but 
where the southern road crosses a white-soil ridge a little further east- 
ward, the dip is 10° or more to the west. East of the ridge there is a 
rapid descent into the open valley of the Kanab (altitude, 6700’ ), eroded 
in the Cretaceous sandstones and shales and somewhat lower than the 
neighboring valley of the Virgin. The fault must pass close to the 
notch where the road crosses the ridge. 
A mile north of another notch in which the northern road crosses the 
ridge of west-dipping Tertiaries, the Cretaceous strata rise in a hill ad- 
joining the Tertiaries on the east, and here a ravine close along the fault 
line almost discloses the actual surface of faulting. The yellow-brown 
sandstones and gray shales of the Cretaceous dip 20° NW., while the 
white Tertiary limestones and shales dip about 10° W., but their bedding 
is not clearly shown. These dips, it will be observed, are locally reversed 
from the eastward slope of the presumably earlier monoclinal flexure and 
evidently result from the drag of the fault. The course of the fault line, 
measured by the trend of the ridge that follows it so closely, is here 
S. 25° W., true bearing. The valley of Kanab creek is broadly opened, and 
the general front of the Pink cliffs rises to the Paunsagunt plateau, attain- 
ing an altitude of nine thousand feet, about eight miles east of the fault 
line. The profile of the plateau is indented by the high-level valleys of 
east-flowing streams, whose heads are constantly undercut by the en- 
croaching ,branches of the Kanab. 
In view of these various facts, it seems inadmissible to regard the 
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