WOLVERINE CREEK. 181 



fault runs along the west base of the ridge, but the line of displacement 

 can not be traced, and its northern end is lost in the breccias and rhyolites. 

 At the extreme northern end, near the bend of Coulter Creek, there is a 

 capping of rhyolite, but between this rhyolite and the higher parts of the 

 ridge the top of the mountain is covered with loose sand and coarse gravel, 

 derived from the wearing away of Pinyon Peak conglomerate. 



The entire ridge is apparently made up of 3-ellowish-brown sandstones 

 of the Montana formation. In places the sandstone is massive, but in others 

 it is well bedded. Wherever observed the beds dip to the southwest, and 

 the entire ridge is probably a massive block of upper Cretaceous sandstones, 

 dipping* away from Mount Hancock and Big Game Ridge. 



REGION OF WOLVERINE CREEK. 



Wolverine Creek finds its source high up on the west slopes of Big 

 Game Ridge, and flows westerly for 9 miles, joining Coulter Creek a short 

 distance above the mouth of the latter stream. Compared with other high 

 mountain streams in this region tributary to the Snake, it runs through a 

 broad open valley, rough and rugged much of the way, but interspersed 

 with green meadows and wide areas of alluvial bottom. The mountains 

 rise high above the stream, the valley being practically shut in by steep 

 slopes and high walls on all sides. 



On the north side the long steep spurs of Mount Hancock tower above 

 the valley for 1,500 feet to the summit of Big Game Ridge. On the south 

 side the mountains stand out with even greater abruptness, and are more 

 irregular in outline, with the lower slopes largely covered with timber and 

 heavy accumulations of glacial drift, For the greater part of the distance 

 the valley is cut in sandstones assigned either to the Montana or to the 

 Laramie formation. Near the mouth of Wolverine Creek stands a grand 

 escarpment of somber breccia, presenting a fine section in many ways 

 typical of large masses of this rock. 



Beyond this wall the stream bottom is impassable, and the trail ascends 

 a steep hillside, crossing a spur of the mountain for 2 miles through a densely 

 wooded country covered with soil and without any good rock exposures. 

 This spur forms a part of the main mass, lying between Coulter and Wolver- 

 ine creeks, and as exposed on both streams consists mainly of basic breccia 

 resting upon a base of Cretaceous sandstone. According to Prof. J. P. 

 Iddings, this mass is capped by a broad table of rhyolite 3 miles in length, 



