198 GEOLOGY OF THE EUREKA DISTRICT. 



Feet, 



5. Bluish black limestone in tbiu layers, overlain by shaly limestone, with 



intercalated beds of bluish black limestone. The limestone in layers 

 gradually replaces the shaly limestone until the latter disappears 

 from the section. Upper beds characterized by Lower Carboniferous 



fauna. (List follows the section.) 390 



At 95 feet from the top, Spirifera lineata and Spirifera cristata were 

 observed. 



DEVONIAN. 



At 140 feet from the top, numerous fragments of crinoids, crinoidal 

 columns were seen for the last time, and Atrypa reticularis began to 

 appear. 



At 350 feet from the top, buff shaly limestone predominates and a more 

 evenly grained, smoother, harder limestone begins to appear as thin 

 layers in the shaly limestones. Fossils few in number and badly pre- 

 served. 



6. Hard, compact, yellowish sandstone in thin layers 25 



7. Calcareous sandstone overlain by arenaceous limestone, and above that 



bluish gray thin bedded limestone 175 



8. Gray siliceous limestone with shaly limestone partings and bands of bluish 



black limestone 340 



At 125 feet from the top, a band of bluish black thinly bedded limestone 



carries numerous fossils of the Upper Devonian age. (List follows 



the section.) 

 At 240 feet from the top, Stromatopora and coralline markings appear. 



9. Hard buff colored sandstone 25 



10. This is almost a repetition of No. 8, the three grading into each other in 



places 225 



Seventy-five feet down from the top, Stromatopora and a small slender 

 coralline stem crowd the darker siliceous layers. 



11. Light gray siliceous limestone, almost a sandstone in places, passing up 



into a dark siliceous limestone, and then into thinner bedded bluish 



black and bluish limestone 1, 920 



The upper layers contain Strophomena pvrplana, Atrypa reticularis, Cyr- 

 tina, sp.f Pleurotomaria. 



12. Gray quartzitic sandstone in massive layers 100 



13. Gray siliceous limestone 110 



14. Quartzitic ferruginous sandstone 85 



15. Light gray and dirty brown siliceous limestone in alternating bands of 



color, of varying degrees of hardness. The siliceous and calcareous 

 matter varies considerably in the different layers. Toward the lower 

 portion many layers are almost made up of a species of Stromatopora 

 and slender stems of a branching coral one-eighth to one-fourth of an 

 inch in diameter 2, 100 



