OF ARTS AND SCIENCES. 



231 



Lower Part of the Eureka Section, Nevada, 12,700 feet. Eastern N.America. 



o c 

 c'c3 

 .5 c- 





Lone Moun- 

 tain lime- 

 stone. 



Feet. 



1,800 Isotelus gigas, Trinucleus concen- 

 tricus, Iltenus, Leptiena, Cerau- 

 rus, Orthoceras,Cytoceras, Chae- 

 tetes. 



Cliamplain 

 Group or 

 Cambrian. 



E o 

 c- 



o 



o 



a 



'S 

 o 



Eureka 

 quartzite. 



500 



No fossils yet found. 



Potsdam 

 sandstone? 



Pogonip 

 limestone. 



J,700 



Blue limestone with distinctly 

 bedded structure ; containing 

 colonies of tlie second fauna, 

 mingleil with and among pri- 

 mordial fossils, Dikeloceplialus! 

 Crepicephalus Gallatinensis ! ! ! 

 Agnostus, Acrotreta, Obolel- 

 la, Lingula manticula ! ! Lin- 

 gulepis, Iltenus, Bathyurus, 

 Asaphus, Amphion, Cystolites, 

 Orthoceras, Maclurea, Orthis, 

 Chaetetes, and a Graptolites. 



Swanton 

 slates. 



Hamburg 



shale. 



350 



Dikelocephalus ! Oonocephalites, 

 Crepicephalus Gallatinensis! ! ! 

 Agnostus, Kutorgina, Obolella, 

 Lingula manticula!! Lingulepis. 



Plamburg 

 limestone. 



Secret Caiion 

 shale. 



1,200 



Dikeldcephalus (2)1 Conocepha- 

 lites (4), Crepicephalus Gallati- 

 nensis ! ! ! and 5 others, Chario- 

 cep]ialus,Oxygia,.\gnostus (4), 

 Hyolitlies, Kutorgina, Acrotre- 

 ta, Iphidea, Lingula manticula ! ! 

 Lingulepis. 



1,600 



Prospect 

 Mountain 

 limestone. 



3,050 



No fossils in sbale; a few imper- 

 fect fragments in calcareous beds. 



300 ft. of shaly beds with fossils : 

 Dikelocephalus ! Conocephali- 

 tes, Crepicephalus Gallatinen- 

 sis !! ! Agnostus, Lingula man- 

 ticula ! ! Obolella. 



2,000 ft. of Magnesian limestone. 

 No fossils. 



Conoccphalites Prospcctensis, Di- 

 kelocephalus ! Agnostus, Sce- 

 nella. 



500 ft. of Magnesian limestone and 

 shales in lenticular or wedge- 

 shaped bodies. No fossils. 



Phillipsburgh 

 or Point 

 Levis 

 Group. 



c 

 ■I 



3 



»3 



100 ft. of red arenaceous shale 

 or Olenellus shales. Olenellus 

 Barrandi,0. Iddingsi.O abnor- 

 mis, Conoccphalites, Acrotreta. 



Prospect 

 Mountain 

 quartzite. 



1,500 



No fossils. 



Granite below the quartzite. 



Note. — Plane of unconformity indicated by double dividing line. 

 * Very likely a break or unconformity of some kind exists here. 



