348 DESCEIPTIVE GEOLOGY. 



Range. The straightness of its walls, which on the southern side are 

 almost perpendicular, and their general parallelism to the southern line of 

 the Cottonwood Archaean body, suggest that its course has at least been 

 determined by, and possibly its shape is largely due to, a fracturing of the 

 strata which form the ridge, through which it is cut. The rocks fonning 

 the western shoulder of this ridge are so covered by, detritus at the mouth 

 of the canon, that nothing can be determined as to its structm-e, though it 

 presumably represents the northern point of the fold seen in Rock Caiion. 

 About 2 miles up the canon, the fault-line is represented by deep north and 

 south ravines, bounded on the east by a straight wall of limestones, in 

 which, on the southern side, the evidence of this faulting is seen in the 

 curving of the strata, as is shown in Plate XIV. This view represents the 

 wall of the canon just west of one of the two beautiful cascades, which fall 

 from the northern slopes of Provo Peaks into the canon from the south ; in 

 this, though the volume of water is not great, the height from which it 

 comes, falling over a ledge over 1,000 feet above the canon-bottom, in one 

 leap of about 600 feet, together with the lace-like appearance of its foaming 

 waters as they ripple over the rugged edges of the strata of dark limestone, 

 render it a most picturesque and pleasing addition to the grand but some- 

 what forbidding scenery of this alpine gorge. The other cascade, which is 

 a mile or two above, still on the southern side of the canon, is less promi- 

 nent, but equally picturesque, being seen high up on the limestone walls, a 

 silver fringe upon their background of deep blue. 



Throughout the length of the canon were observed only beds of the 

 Wahsatch limestone, though some of the lower groups may have escaped 

 notice near its mouth. They are dark blue and gray in color, generally in 

 heavy strata, though sometimes thinly bedded, and containing developments 

 of slates and argilHtes.^ The beds dip eastward, generally at low angles, 

 though in some places showing steep dips. No distinct evidences of exten- 

 sive faulting east of the line of the cliffs represented in Plate XIV was, 

 however, observed. 



^Mr. Henry Engeiniann mentions the discovery of a fragment of Lepidodendron in 

 slates, and of carbonaceous matter in bluish-black argillaceous slates in this canon. 

 He also obtained a Froductus semistriatus and an undetermiued Athyris from the canon, 

 without defining the horizon.— (Capt. J. H. Simpson, Expls. in 1859, 309, 369.) 



