GENERAL STRUCTUEE OP THE TUSHAR. 



173 



toward the basin type. The latter may be represented by conceiving the 

 strata forming the platform of a given tract to be rent by a long fault, and 

 upon one side of it to be lifted and tilted at a considerable angle. This 

 inclined mass is usually further fractured by smaller faults rudely parallel 

 to the principal one, and complicated by more or less warping. The 

 plateaus also are usually tilted, the Aquarius and Kaibab being most nearly 

 horizontal. But there is a marked difference between the two types in the 

 amount of inclination. In the plateaus it seldom exceeds three degrees; in 

 the basin it is rarely less than ten. In the plateaus the warping and minor 

 displacements are seldom important, and the whole aspect is calm and even; 

 in the basin they are extensive, and the aspect is wild and distorted. In 

 the plateaus, the obvious characteristic features are the broad platforms of 

 the tables, the gently sloping terraces and the majestic repose of the mighty 

 cliffs which bound them; in the basin, they are the sharp ridges, cusp-like 

 teeth, and tumultuous slopes of sierras. Probably the cori-ect view to be 

 drawn from a comparison of the two structures is that the basin type repre- 

 sents an advanced stage of an action which has been impei'fectly developed 

 in the plateaus. Had the tables been pushed up higher, they might have 

 been as much inclined as the sierras and as much comminuted and distorted. 



The Tushar is in some portions at least, and so far as observed in most 

 portions, more inclined than any other of the High Plateaus, but so far as 

 can now be discerned it approaches more nearly to the tabular than to the 

 sierra type. Lying within tlie geographical limits of the Great Basin, it is 

 not surprising that it should show an apjjroach to the structure of the latter 

 province. It may be regarded as indicating a transition between the two 

 forms, though more nearly allied to those peculiar to the Plateau Pi-ovince. 



It is difficult, however, to realize this conclusion as being a true one 

 when we stand upon the southern termination of the Pdvant, and look at 

 the cluster of peaks which crown the summit of the Tushar. Two noble 

 cones ending in sharp cusps stand pre-eminent, while behind them numer- 

 ous dome-like masses rise to nearly the same altitudes. The two peaks are 

 Belknap and Baldy, which reach above the timber-line, and are very strik- 

 ing on account of the light cream-color of their steep slopes and the ashy- 

 gray tips of the apices. These pyramids are not apparently the remains 



