30 SOUTHWESTERN NEVADA AND EASTERN CALIFORNIA. 
CARBONIFEROUS. 
Hague a describes the Weber conglomerate at Eureka as consisting 
of 2,000 feet of coarse and line conglomerate containing angular and 
rounded fragments of chert, interbedded with reddish-yellow sand- 
stones, and lying conformably between the limestones of the lower 
and the upper " Coal Measures." In the Belted Range the Pennsyl- 
vania]! limestone is underlain by 300 to 500 feet of shale, which in 
turn overlies 800 to 1.000 feet of sandstone. The shales are thin 
bedded and of green, gray, or brown color. The sandstone is in 
part a rather pure quartzose rock and in part an arkose. Inter- 
bedded conglomerates contain well-rounded pebbles of limestone, 
quartzite, flint, and jasperoid, evidently derived from early Paleo- 
zoic rocks. Lithologically similar beds occur in the Cactus Range. 
These rocks are probably the equivalent of the Weber conglomerate 
at Eureka. 
Pennsylvanian limestone also occurs in the Panamint and Reveille 
ranges and forms a small area on Shoshone Mountain. This limestone 
is dense, dark gray or black, and fine to medium grained. Specimens 
from many }n^\< emit a fetid odor when hit with the hammer. Nod- 
ules of black Hint are characteristic at many horizons. The limestone 
in the Belted Range, 2,500 feet thick, has near its center 55 feet of 
limestone conglomerate. 
POST-JURASSIC AND PRE-TERTIARY IGNEOUS ROCKS. 
The granite and associated rocks of the Belted and Panamint 
ranges, of Pahute Mesa, and of the Gold Mountain ridge contain 
fragments of gray, fine-grained monzonite and quartz-monzonite 
porphyry. These fragments, while clearly somewhat older than the] 
rocks in which they occur, are massive and possibly represent an 
earlier solidification of the magma, from which the granitic rocks were] 
afterwards differentiated. These rocks include types ranging on 
l lie one hand from alaskite through muscovite, muscovite-biotite, and 
biotite granites to a quartz monzonite approaching granodiorite,| 
and on the other hand from a soda-rich granite to soda syenita 
While the granitoid rocks in the areas shown on the map are of] 
rather constant composition, transitions occur in a single area. Ii 
the Gold Mountain ridge, for example, of two ledges separated bl 
less than 10 feet, one is a microcline-granite porphyry and the other 
a hornblende - bearing quartz - monzonite porphyry. Porphyrith 
types of the granitoid rocks occur, as well as aplites and pegmatites 
later differentiations of the same magma. 
These granitoid rocks are widely distributed over the region undei 
consideration, although they cover larger areas in the western portioi 
a Hague, Arnold, Mon. U. S. Geol. Survey, vol. 20, 1892, pp. 91-92. 
