7 
HUNTINGTON AND GOLDTHWAIT: THE HURRICANE FAULT. 223 
probability be the case on such an uplifted coastal plain, the main 
rivers ran eastward, in a direction opposite to that which they now 
follow. 
The First Faulting. 
We may now consider the first faulting, whereby these monoclines, 
which ran north and south, were cut longitudinally by great faults. 
The plateau region now became a series of blocks, separated by faults, 
which in each case involved an uplift on the east and a downthrow on 
the west. Dutton (¢, pp. 21, 41, 113), Gilbert (a, p. 54), and Marvin 
(p. 196), all speak of the fact that all the great faults of the plateau 
region, which at present determine the leading features of the topography, 
follow the lines of older monoclinal flexures that dip east. ‘It is cer- 
tainly remarkable that the distinct flexures of the Grand Canyon dis- 
trict dip eastward so generally, while the faults have their throw to the 
west with almost equal regularity. In all cases where this obtains, the 
later movement by faulting was of greater measure than the earlier move- 
ment by flexing. It is further noteworthy that the unfaulted or least 
faulted flexures . . . lie to the east, while the distinctly faulted flexures 
lie. to the west” (Davis, b, p. 149). 
The fact that the displacement by faulting is exactly opposite in its 
vertical effect to the earlier movement by flexing seems to indicate that 
the two movements represent two distinct periods of uplift, —an earlier 
one which, in the Toquerville district at least, witnessed tangential 
pressure of the Appalachian sort, and a later one in which there was 
only vertical uplift. 
The fault with which we are chiefly concerned — the old Hurricane fault 
— may be traced from the Colorado river northward one hundred miles 
to Kanarra. It probably extends far beyond these limits; but that is a 
matter for future study. At Coal spring, twenty miles north of the Col- 
orado river, we first saw the old fault; next we visited it at a point on 
the Hurricane, fifteen miles north of Coal spring; and again, after an in- 
terval of twenty-five miles, near Antelope wash. From near Fort Pierce, 
about on the Utah boundary, we followed it to Kanarra, making this 
portion of the fault line our special study. Along this part, the Utah 
part, of the Hurricane, the evidence of the old fault is associated in 
rather a confusing way with the more apparent evidence of the second 
faulting, which is much more recent, and gave rise to the present Hur- 
ricane scarp. South of the Arizona line, however, the Hurricane fault, 
