152 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
than supposed by Dutton, and concluded that it joined the northern 
end of the Toroweap Fault, or in other words, that the Sevier and 
Toroweaj) Faults were one and the same. He therefore describes 
the two as a single fault, under the name "Sevier-Toroweaj) Fault" 
(Davis '01, p. 143-144; '03, pp. 3, 4, 17-18). 
In making our trip from Pipe Spring to the Toroweap Valley we 
traced the ])osition of the Sevier Fault to a point some miles southwest 
of Cedar Knoll. Continuing in a more westerly direction, we en- 
countered a low monocline which gradually increased in height as we 
followed it southwest. Later this monocline gave place to a fault, 
which we traced practically without interruption into the Toroweap 
Valley, proving that it was the Toroweap Fault (fig. A, T.). We 
concluded, therefore, that the two faults were independent, and that 
the Toroweap Fault died out north of the Caiion, as supposed by 
Dutton; the Sevier Fault, however, continued much farther south 
than he supposed. Plate 19, figure 1, shows the Toroweap monocline 
near where we first encountered it, west of the Wild Band Pockets, 
the displacement at this point being only fifty feet. Climbing to the 
summit of this low hill, the escarpment of the Sevier Fault could be 
distinctly seen six or eight miles away, toward the southeast. 
In plan, the Toroweap monocline curves quite distinctly, as shown 
in the sketch map (fig. A). In section it appears as a simple mono- 
clinal fold of gentle inclination toward its northeastern part, where the 
displacement is of small amount (pi. 19, fig. 1). Still farther north- 
east the limestones have passed beneath the surface, and the monocline 
developed in the overlying shales has been planed ofi' by erosion. Its 
presence can be detected in the dip of the shales as exposed in the 
gullies near the Wild Band Pockets. Toward the southwest the 
displacement increases in amount, and the simple monocline changes 
to a double monoclinal fold, similar to the double portion of the East 
Kaibab ^Monocline although on a much smaller scale. How far this 
double character is maintained we did not ascertain, but it is well 
shown in a ravine traversing the fold several miles west of Sawyer's 
Tank. At some point near the head of the Toroweap Valley proper 
the monocline changes to a fault (pi. 19, fig. 2) which increases in 
throw toward the south, the displacement amounting to 600 or 700 feet 
at the Canon, according to Dutton ('82, p. 93). It is thus certain that 
the northward decrease in the amount of displacement, described by 
Dutton, is really present, and that it cannot be explained as an appar- 
