132 (lEOLOdY OF THE EUKEKA IHSTKICT. 



and soutlnvest of I'iuuacle Peak, the beds dipping- to the southeast at a h>w 

 angle and striking northeast and southwest. These beds yiekk'd tlie fok 

 lowing forms: 



Thecia ramosa. Dystactella iusularis. 



Aulopora serpens. Conocardium uevacleusis. 



Chouetes deflecta. Loxonema siibatteiuiata. 



Spirifera pirioneiisis. Bellerophon perplexa. 



Atrj^i^a reticularis. Tentaculites sealariforiuis. 

 Rhyuchouella occideus. 



Nearly all these species occur in the shale belts of Atrypa Peak, Brush 

 Peak, and Combs Mountain, the exceptions being the three species, Thecia 

 ramosa, Aulopora serpens, and Dystactella insularis, which are, hoAvever, 

 characteristic of the upper Helderberg in New York and Ohio; Thecia 

 ramosa and Dystactella insularis have only as yet been found at this one 

 locality at Eureka. A smaller but somewhat similar g-rouping- of fossils 

 occurs in the limestone just west of Lookout Mountain, Avhere the}- are 

 associated with Strophodonta canace, a species found b^' the writer in the 

 limestone at Treasure Hill, White Pine. 



On the west slo})e of Pinnacle Peak the beds dip toward tlie fault at 

 an angle of 10°, reaching to within 150 feet of the summit and lying- un- 

 conformably against the ICureka quartzite of the peak. FolloAving tlie line 

 of the fault the beds trend oif to the southeast, the quartzite belt gradually 

 narrowing until lost beneath the pumices, the Nevada limestone, on the 

 other hand, continuing southward in a low ridge bounded t>n the east and 

 west sides b}- igneous rocks. The beds exhibit much the same habit as 

 those to the northward, usually light in color and hig-hly siliceous, Ijiit show- 

 ing more distinct lines of bedding. By reference to the map (atlas sheet xi) 

 the structure will be seen indicated by strikes and dips. South Hill, the 

 most prominent jjoint on this southern extension, has a marked anticlinal 

 fold, the axis of the fold striking N. 40° to 45° east, with a dip of 15°. 

 The brownish gray limestones are distinctly bedded and probably belong to 

 a somewhat higher horizon than any of those exposed in Grays Canyon. 

 South of the road, which traverses the ridge near its southern extremit}', a 

 well defined but gentle synclinal fold may be seen crossing the ridge 



