DAVIS: THE GRAND CANYON OF THE COLORADO. 147 



opportunity of attacking the strata here concerned ; for, as in the case 

 of the Toroweap fault, until renewed uplift introduced the canyon cycle, 

 it must be supposed that the strata in the Hurricane ledge of to-day 

 were close to or even beneath baselevel, and hence out of reach of 

 erosion. On the other hand, a branch of the main Hurricane fault cuts 

 certain lava beds, — not the most recent ones (c, pp. 116, 117), — and 

 this branch must be younger than the lavas, which in turn must at the 

 oldest have been erupted late in the plateau cycle. 



The Hurricane fault seemed to me to fade away just north of Virgin 

 river. The line of great cliffs that comes up from the south here gives 

 place to a monoclinal flexure, dipping to the west in sympathy with the 

 throw of the fault ; and a few miles further north the flexure loses im- 

 portance, as far as we could interpret its structure in the view from the 

 escarpment south of the river. A new displacement seemed to begin 

 two or three miles to the west, rapidly increasing its throw northward 

 and so continuing from Toquerville past Belleview, Kanarra, and beyond, 

 where it sharply separates the Plateau province from the Basin range 

 province. The southern termination of this displacement was not cer- 

 tainly determined. As a fault, it ends just south of Toquerville, but it 

 may turn southwest and find a continuation in the anticline at the 

 eastern base of Pine valley mountain. In any case it seemed entirely 

 independent of the Hurricane fault proper. The course of Virgin 

 river hereabouts is perhaps consequent upon the overlap of these dis- 

 placements, for it lies close to the sag between them. It may be added 

 that, although we had a fine view northward into the valley of Le 

 Verkin creek from the rim of Hurricane ledge, we did not detect the 

 lapse of the Permian and the unconformable overlap of the Trias on the 

 Carboniferous, as noted by Howell (p. 285) ; but to assert the non- 

 occurrence of these features would be going too far. The neighborhood 

 of Toquerville offers an unrivalled field for special study. The village 

 serves as a good base of supplies, the surrounding district is traversed 

 by many roads and trails, stratified rocks range from Carboniferous to 

 Tertiary, igneous rocks are present in good variety, the structural 

 features are of unusual interest, denudation has been enormous, and 

 the half-desert scenery is superb in form and color. 



The Grand Wash Fault is said by Dutton to be no older than Pliocene 

 (c, p. 191) ; yet the work of erosion after the fault had attained a strong 

 measure of displacement would give it a much greater antiquity, for 

 while a monoclinal slice of the Trias is preserved along its thrown (west- 

 ern) side, there is no Trias on the heaved Shivwits block for fifty miles 



