WILDCAT PEAK. 169 



elevation, are flat-topped, and easily accessible. Numerous groups of conif- 

 erous trees, broad areas of grassy upland, and an abundance of water add 

 great charm to the region. South of Wildcat Peak the country falls away 

 in long- monotonous ridges, with narrow intervening valleys, uniform in out- 

 line and dreary in aspect. Structurally this uplifted mass, in its simplest 

 form, presents a synclinal fold, whose axis, with a broad sweeping curve, 

 strikes obliquely across the mountains northwest to southeast. This struc- 

 ture is accompanied by local crumpling and folding of beds. Apparently 

 the force uplifting the beds upon the southern side of the fold came from 

 the direction of the Teton Range. Wherever observed these beds dip 

 persistently into the mountains and away from the Archean mass which 

 forms so broad and continuous a body to the southwest. Owing to the 

 crumbling nature of the beds and the amount of soil, good rock exposures 

 are rarely seen. Along the banks of Lizard Creek and the adjoining 

 valleys to the east and west the beds lie inclined from 20° to 30° NE. The 

 axis of the syncline trends across the southern and western slopes of Wild- 

 cat Peak, and is lost beneath the rhyolite forming the steep slopes toward 

 Snake River. 



wildcat Peak. — At the base of Wildcat Peak, near the head of Lizard 

 Creek, the beds dip slightly to the northeast, but those forming the summit 

 of the peak belong to the opposite side of the syncline and are highly 

 inclined, many of them standing on edge. Here they trend diagonally 

 across the ridge, with a dip varying from 65° to 70°. The strata are thinly 

 bedded sandstones, presenting long rows of slab-like exposures. These are 

 underlain by black arenaceous shales, in turn followed by other thin layers 

 of sandstone. The beds striking across the ridge give rise to narrow lateral 

 spurs, with deeply eroded ravines between them. Along the summit of the 

 ridge the same beds may be traced eastward with apparently the same dip 

 and strike- In the open park-like country northwest of Wildcat Peak and 

 west of Huckleberry Mountain the beds show a southerly dip, indicating 

 the north side of the syncline. The beds found on both sides of the axis 

 of this fold have been referred to the Montana formation. It is possible 

 that they include a series of beds which should be assigned to the Colo- 

 rado, but, owing to the present state of knowledge and the very limited 

 number of organic forms as yet obtained from this region, it has been 

 found impossible to draw any line of demarcation between the two periods 



