122 SOUTHWESTERN NEVADA AND EASTERN CALIFORNIA. 
The Pennsylvania n limestone appears to overlie the Weber conglom- 
erate conformably. The formation is fossiliferous, and collections 
were made ± miles south of Oak Spring and at several horizons 
northeast of Tippipah Spring. Dr. George H. Girty kindly made 
the following determinations of Pennsylvanian fossils, the first four 
Lots being found beneath the limestone conglomerate and the fifth 
above it. 
Fossils from Pennsylvanian limestone in Belted Range. 
LOT 1. 
Fenestella sp. Productus sp. 
Rhombopora sp. Aviculipecten ? sp. 
« Jhonetes sp. Phillipsia sp. 
Productus cora V 
LOT 2 
Fusulina sp, Marginifera ? sp. 
Rhombopora sp. Seminula sp. 
Archaeocidras sp. Aviculipecten sp. 
I >erbya ? sp. 
LOT 3. 
Chonetes sp. afE. C. permianus. Leda? sp. 
Seminula sp. 
LCT 1. 
Zaphrentis sp. Marginifera? sp. 
Rhombopora sp. Ambocoelia V sp. 
Stenopora sp. cf. S. carbonarla. Derbya? sp. 
LOT 5. 
Rhombopora sp. Productus sp. cf. P. semireticulatus. 
Stenopora? n. sp. Productus nevadensis? 
Siebert lake beds.- -Siebert lake beds cover considerable area- nortl 
of Oak and Whiterock springs, and a number of -mall outliers occui 
on the Carboniferous rock- near by, indicating that the lake bedl 
were at one time continuous with those of Pahute Mesa. Anothei 
outcrop lie- south of Wheelbarrow Peak', and to the east there an 
-mailer areas not mapped. 
A section at Oak Spring i- a- follows: 
Section <it <><tl: Spring. 
Feet 
Later rhyolite -5« 
Well-bedded, incoherent sandstones and conglomerates; white with some 
dark gray bands. Many of the layers, which are from '2 to 1 feet thick, 
show cross-bedding. Crystals of glassy feldspar, quartz, ami biotite are 
abundant in some beds and lacking in others. The pebbles in the con- 
glomerate for the mosl pari are small, but some of them roach 6 inches 
in diameter , 20) 
Later rhyolite . 4 1 
White sediments as above 10 
Later rhyolite n 
Salmon pink, white, and yellow sediments as above 28 
