piSoN HAN(;i:. 



201 



The tdlldwiui;- ideal section was made bv Mr. Walcott: 



S.jE. 





^ 



J'oyoi Lip 



Xunnstoru:,. 





LcnieAftrL. 

 Z, LTTU^torie. 



m 



Pd'onxoTi. 



CarbuTtz/trous 

 QcuzrCztee-. 



Fin. 4. — Section across Pii 



Across tlie range from west to east along- the line of the section a dark 

 blue limestone, carrying a few fossils of the Lower Devonian, rises above 

 the plain. Beyond the limestone a sharp oblique fault brings up a Itroad 

 mass of quartzite, conglomerates, and l)lack siliceous pebbles. These, in 

 turn, are conformabh- underlain by l)lue limestone, from which a sufficient 

 fauna was secured to identify Upper Devonian beds. The limestones are 

 again cut otf by a profound fault, a]iparently along a line of an anticlinal 

 axis. To the west of this fault the l)eds all dip westward, but beyond this 

 point jiresent an casterh- dip, at least as far as the V)ase of Pinto Peak. 

 Directlv eastward of the fault a dark ferruginous (piartzite stands out 

 prominentlv, followed by light gray siliceous limestones, the age of which 

 is determined by the presence of Halysites. The beds gradually assume the 

 lial)it of the Devonian and carry a fauna sufficiently characteristic to estab- 

 lish the horizon of the Lower Devonian, and still higher uj) in the series 

 yielded Upper Devonian species. Overlying the limestones occurs a great 

 thickness of quartzites and sandstones, with occasional argillaceous bed. 

 Near the juucti(Mi of the Devonian limestones with the overlying quartzites 

 the beds upon l)oth sides of the anticline are identical, showing the corre- 

 sponding horizons without the evidence of the fauna. If the White Pine 

 shale of Eureka is at all i-epresented In the Pinon Range it is found in the 

 argillaceous and finely siliceous l)eds innnediately overlying the Devonian 

 limestones on both sides of the fault. These beds resemlde those ol)served 

 at the same horizon at The Uate, already described, and the continuance 

 uiirthward of siniilar sediments is not without interest, especially when 

 taken in connection with the great thickness of White Pine shale to the 

 southeast as developetl in the Diamond Range, Cliii" Hills and White Pine. 



