IIANGKS OK NOKTHWKSTEUN UTAH 221 



Oinhe moutUains. — The Ombe mountains are .situated at the extreme 

 western eilge of Utah, near the Nevada Hue. Aecording to Mr Kinjj;,'*' 

 the strueture in the southern portion is an anticlinal Ibid, which has a 

 northeast-southwest strike, and thus diverges from the <>jeneral north- 

 and-south trend of the range. Northward this fold is succeeded, on 

 account of this divergence, by the adjacent synclinal. Still farther north- 

 ward the entire range has a uniform westerly dij), apparently rei)r<jsent- 

 ing one side of the next anticlinal fold, the other side having been re- 

 moved by erosion. The east face of this portion of the mountains is a 

 steep escarpment several thousand feet high, which is sui)posed by Mr 

 King to be a fault scarp. Mr Hague,t who has described in detail the 

 range, and from whose descriptions INIr King's conclusions are presum- 

 ably drawn, does not mention the fault, although agreeing with the 

 descrii)tion already given of the folds. 



From the above, especially the fact of the ridge being for at least a 

 portion of its length synclinal, it is probable that the mountains, on the 

 whole, are due to erosion. 



Resume of structure of ranges of northwestern Utah. — In summing up the 

 characteristics of the different ranges described, it has been seen that in 

 every case so far as known they owe their jjrincipal features to deep, 

 long continued erosion and not primarily to deformation, expressed 

 either by faults or folds. The folds have frequently been so eroded that 

 synclines form the mountain crest ; indeed, the synclinal and the anti- 

 clinal ranges appear about equally abundant. There are several steep 

 scarps, which have been described as fault scarps, but so far as the writer 

 can make out there is no evidence that a fault exists along them. 



RANGES OF NORTHEASTERN NEVADA 



Gosiute range. — According to Mr King, J the Gosiute range, which lies 

 next west of the Ombe range, consists essentially of a single anticlinal 

 fold. The central portion, however, is a monoclinal ridge, which is a 

 limb of the anticlinal, the other limb having been removed. Mr King 

 remarks that any one passing by this central part might easily be mis- 

 taken so far as to suppose the range to be a single monoclinal mass 

 formed by dislocation and tilting. 



Since, according to Mr King, the half of the anticlinal fold has not 

 been removed from the central part of the range by faulting, it must 

 have been done by eroson. In the face of erosion so powerful as this 

 we must believe that it has determined the structure of the mountains 

 in general. 



*Geologicals Exploration of tlie Fortieth Parallel, vol. i, p. 7o(5. 



fGeologicals Exploration of the Fortietli Parallel, vol. ii, Descriptive Geology, p. 41)5. 



tOp. cit., p. 737. , 



