HUNTINGTON AND GOLDTHWAIT: THE HURRICANE FAULT. 241 
sideration is the displacement itself, — its measure and plan, horizontally 
and vertically, and its date. This part of the subject is the only portion 
that is commonly treated systematically and fully. It represents the 
vertical component of the diagrams of Fig. 9. It is more definite and 
more easily worked out than the other divisions of the subject, and can 
be more easily stated, but it is of no greater importance. The case is 
analogous to that of mountains where the ridges and peaks, the cul- 
minating portions, are easy to apprehend and have been mapped and 
described again and again, while the slopes in spite of their varied form 
and great extent are passed over without minute observation and are 
almost never well described. (3) The third division involved in a treat- 
ment of faults is the changes that have taken place since the displace- 
ment. It is usually tacitly assumed that a discussion of these is 
necessary, but the subject is commonly dismissed in a few sentences, 
as though it were something that every one could picture for himself. 
Yet such is by no means the case. Definite, careful statement is as 
essential here as it is in the description of the fault itself. 
In our account of the first folding and of the earlier Hurricane fault 
we have briefly considered these three aspects. In what follows we shall 
treat the later faulting in the same way, but with more detail. The 
topographic condition of the country has already been considered under 
the head of the inter-fault cycle of erosion. It is further necessary to 
restore the whole region to its former attitude with respect to sea-level, 
including the relatively downthrown as well as the uplifted portions. 
We shall begin with the most elevated block, which was probably also 
the one that last suffered movement, and shall restore the different parts 
to their places in an order inverse to that in which they were displaced. 
The first step in this process is to lower the upheaved block east of the 
Hurricane fault until its lava sheets match those of the downthrown 
block to the west. This, however is not enough, for, as we shall see 
later, a very considerable part of the uplift that introduced the canyon 
cycle took place along the Grand Wash fault. If the region disturbed 
by this latter displacement is restored in the same manner to its former 
position, we find that the southern end of the Shivwits plateau is thereby 
lowered from its present elevation of six thousand feet to only one hun- 
dred or fifteen hundred feet. At the northern end of the Grand Wash 
fault, however, in the valley of the Virgin, the Shivwits plateau, of which 
the lowest points are now at an elevation of from twenty-five hundred 
to three thousand feet, is not depressed at all by restoration, while the 
northern part of the Uinkaret plateau just to the east of the Hurricane 
