OWI-YUKUTS PLATEAU. 273 



northward were observed, and the strikes are very irregular, but generally 

 east and west, with a tendency to the southeast. Along the southern base, 

 the limestones, broken into huge blocks, have evidently fallen over the 

 Tertiary beds, which have been deposited around it in the bay now occupied 

 by the valley of Talmantds Creek. This valley itself would seem to have 

 probably owed its position originally to a line of dislocation, since the strikes 

 of the beds on either side show considerable discrepancy. 



To the south of this valley extends a sharp, narrow ridge, which con- 

 stitutes the eastern boundary of the Owi-yu-kuts Plateau, and which is 

 formed by the upturned edges of the limestones and sandstones of the 

 Upper Coal-Measure group, of which a section will be given farther on, 

 having a strike of north 17° west, and a dip of 31° to the northeast. On 

 the plateau to the west of this ridge, the edges of the upturned beds of the 

 Weber Quartzites are seen ribbing the surface, with a strike still more to the 

 westward and a steeper dip. These outcrops extend close up under the 

 limestone cliffs, whose beds might seem to have been deposited unconform- 

 ably over their edges. The evidence at this point, if considered by itself, 

 might seem to favor the idea of a non-conformity between the AVeber 

 Quartzites and the overlying beds. We have been unwilling, however, to 

 accept this e\Tidence as final, from the fact that our observations elsewhere 

 almost invariably point to the opposite conclusion, and would explain the 

 apparent unconformity by a lateral dislocation, which has pushed the lower 

 beds up at a steeper angle, and moved them somewhat to the northward and 

 eastward with respect to the limestone beds which form the cliffs. An evi- 

 dence of this dislocation is seen in a break, about midway in the ridge, now 

 occupied by the deep, narrow caiion of the dry bed of a stream which drains 

 into the Lower Vermillion Creek from the north. As will be seen on the 

 map, this faulting has had the effect of moving the southern portion of the 

 ridge to the eastward. The strata of the upper formations are apparently 

 continuous, however; owing, doubtless, to the greater elasticity of their beds, 

 no actual break took place in them, but the effect of the movement is seen 

 -in the curved strike of the ridges which they form. 



The canon of Vermillion Creek, in the eastern continuation of this 



ridge, a narrow gorge, only a few hundred feet wide, with steep walls, which, 

 18 D G 



