COLUMNAR SECTION. 
i ge contains pebbles of quartzite, jasperoid, and vein or pegmatitic 
•tz derived from pre-Cambrian formations. The mica sch 
Bullfrog Hills is pre-Ordovician, and although considered of Cam- 
Desert gravels. 
older alluviui 
Older alluvium, with Pliocene lake beds at base. 
Rhyolite. 
Siebert lake beds, with rhyolite and basalt flows. 
Unconformity. 
' '>■■:- • ".-.' 
*r^r Unconformity. 
Rhyolite. 
Basic audesite. 
Second rhyolite, with minor basalt flows 
Monzonite porphyry and acid andesite. 
First rhyolite. 
Pennsylvania!! limestone. 
Weber conglomerate. 
lurian. | Lone Mountain limestone. 
Eureka quartzite. 
Pogonip limestone. 
Prospect Mountain limestone. 
Prospect Mountain quartzite. 
Unconformity. 
rp Unconformity. 
Unconformity .a 
Unconformity. 
Unconformity. 
feet 
Fig. 3.— Columnar section of rocks of southwestern Nevada and eastern California. 
brian age, it may be pre-Cambrian. The schist at Trappmans Cam]) 
and the series in the south end of Amargosa and Panamint ranges 
are also probably Cambrian, although possibly pre-Cambrian. 
a Rocks below this are cut by granite, which in turn is cut by monzonite porphyry, and this in turn 
by diorite porphyry. 
