SOUTH WALL OF HORSESHOE GULCH. 163 



beds dip regularly eastward at an angle of 20°. They consist mainly 

 of coarse white or gray sandstones, passing into conglomerates composed 

 largel}' of pebbles of white milky quartz, having a slightly pinkish tinge, and 

 which, when weathered out, cover the surface for a great distance. Alter- 

 nating with these are thinner beds of micaceous quartzite, passing into a 

 mica-schist, the mica being always of the muscovite or potash type. Less 

 frequent are thin seams of black carbonaceous shales. Near the upper part 

 of this portion of the section is a single bed two feet thick of dark iron- 

 stained limestone, seamed with carbonaceous shales. Between this and a 

 little knob rising above the general level of the ridge is a synclinal fold in 

 the beds, which rise on its western side at angles of fi-om 50" to 70°. 

 The beds included in the synclinal trough above the iron-stained bed are, 

 first, a white quartzite conglomerate, then a brownish sandstone, then a 

 white massive sandstone, then a second brownish sandstone with thin .seams 

 of clay and shale, and finally a green clay slate at the axis of the syncline. 

 East of this axis the same succession of beds is passed over, which appear 

 thinner, however, owing to their standing at a steeper angle. On the east 

 side of the knob the iron-stained limestone reappears dipping 70° to the west, 

 and a short distance farther can be traced somewhat indistinctly, dipping 

 at the same angle to the eastward. Following the ridge eastward the beds 

 assume the normal dip of 20° and have the same general character as that 

 already described. For half a mile or more dark thin beds of quartzite and 

 shaly beds are more frequent, but gradually pass up into massive, heavily- 

 bedded, coarse white sandstones, whose dip shallows to about 10° or 15°. 

 This little anticlinal and synclinal fold has the normal character of the folds 

 in this region, viz, a steep v»'est side to the anticline or east side to the syn- 

 cline. It may also, as is often the case, be accompanied by a slight move- 

 ment of displacement, but this could not be definitely proved. The synclinal 

 structure can be traced on the broad ridge directly south of this point in the 

 somewhat indistinct lines on its grassy surface which mark the outcrops of 

 the beds. The fold here becomes broader and shallower, and probably soon 

 dies oiit to the south. 



Lamb Mountain. — Near the wcst end of the little prominence on the ridge 

 called Lamb Mountain, an eruptive rock comes in above the sandstone, 



