240 H. W. TURXER GEOLOGY OF THE SILVER PEAK QUADRANGLE 



with those of the banded limestone which immediately underlies a cal- 

 careous layer containing Archeocyathus. This banded limestone, in 

 which the sedimentation planes are indicated by alternating brown and 

 dark layers one to three inches in thickness, dips 60 degrees to the east, 

 and the sedimentation planes are cut by a schistose structure dipping 

 southwest 10 degrees. The line of contact between the banded limestone 

 and the schists is parallel to the bedding planes of the limestone, and 

 this also suggests conformity. Calcite deposited along the planes of the 

 schistosity brings out the schistose structure plainly. The overlying 

 Archeocyathus limestone likewise shows planes of schistosity cutting the 

 bedding planes. 



Overlying the basal Archeocyathus limestone is slate containing 

 Ethmophyllum, and above this is green Olenellus slate. In the same 

 section, overlying the green Olenellus slates, are thick layers of thin 

 bedded limestone with thin bedded quartzites at the east edge of the 

 quadrangle. 



In Mineral ridge, to the west and northwest of Silver Peak, the Lower 

 Cambrian consists of Olenellus slates and dark fossiliferous limestone 

 overlying massive dolomitic marble and quartzite. 



The Lower Cambrian series as a whole, considering its great age, shows 

 remarkably little alteration, the massive limestones and quartzites fre- 

 quently giving no evidence of crushing. As a result, the fossils are at 

 most points well preserved. At some points, however, as north of Clayton 

 valley, a schistose structure is developed, more especially with the Olenel- 

 lus slates, and is often to be observed where there has been unusual 

 crushing of the rocks. Several of the limestone layers are crowded with 

 little orbicular bodies. These are not certainly of organic origin, but 

 were not found in beds known to be of Upper Cambrian or Ordovician 

 age. 



Analyses of carbonate RocJcs of the Loicer Canibrian 



George Steiger, Analyst 





Dolomite, 



number 



690. 



Dolomite, 



number 



468. 



Dolomite, 



number 



545. 



Limestone, 



number 



563. 



Lime. . . 



28.52 



19.19 



.95 



44 09 



7.18 



30.35 



20.19 



1.89 



47.21 



.31 



34.49 

 11.38 



52.00 



Magnesia 



.42 



Ferrous oxide 18 





Carbon-dioxide 







Insoluble in boiling HC1. 1-3... . 















99.93 



99.95 













Includes any Al ; also any P 9 K or TiO, that may be present. 



