ANTICLI2TAL STRUCTUEE. Hi) 



coniiectidii witli the Eureka ^Mountains by a complicated system of ridfj-es 

 wliicli closelv unites them vvitli botli Prospect Kidye and the Mahog-anj^ 

 Hills. Although their northern limit is very ill defined, they stretch in a 

 north au<l soutli direction for 10 or 12 miles and measure about 5 miles in 

 width, with an elevation above the surrounding valleys of over 2,000 feet. 

 Bellevue and White Cloud Peaks are the two most prominent points in the 

 mountains, the former with an altitude of 8,883 feet, the latter of 8,850 feet 

 above sea level, while between them is a still higher tablc-topjjed suiniuit, 

 having an elevation of 8,!)ol feet above the sea. 



In structure the main body of Fish Creek Mountains consists of an 

 anticlinal fold, whose axis lies along the eastern edg'e of the broad, slighth" 

 inclined table which forms the top of the range. A north and south line 

 of faulting coincides with this axial plane and is accompanied by an escarp- 

 ment, nearly 600 feet in height, showing a downthrow at least equal to 

 that amount. The displacement may be traced readil}' for a considerable 

 distance along the mountain. The fault is not laid down on tlie map, hut 

 the escarpment itself is indicated liy the contour linos l)eing thrown close 

 together. At the base of this cliff the rocks are much broken up, as there 

 appears to be a series of small faults rather than one sharp displacement. 

 The anticline is nevertheless sharply brought out by the limestone di])ping 

 in opposite directions with a marked diffei'ence in the angle of inclination. 

 The beds of the cliff incline at low angles into the mountains, whereas the 

 slopes upon the east side, with an average dip of 15'^, fall away abruptly 

 for about 1,500 feet or until buried beneath the Quaternary deposits of Fish 

 Creek Valley. On the west side of the main axis the limestones assume a 

 gentle synclinal roll, followed by a low, broad anticline, the westerly dip- 

 ping beds of which extend for nearly two miles, with a monotonous uni- 

 form dip, rarely exceeding 5° or 6°, till lost beneath the detrital accumula- 

 tions of Antelope Valley. The geologfcal structure is that of a faulted 

 anticline, gentle on one side and relatively steep on the other, a 

 structure typical of many ranges in the Grreat Basin. Besides the north 

 and soutli anticlinal fold there is a gentle quaquaversal dip from the central 

 mass about Belle\T.ie Peak, the beds to the northward, however, dipping 

 away steeper than in the other directions. 



