66 



GEOLOGY OF THE EUKEKA DISTRICT. 



Nevada limestone Devonian. 



17 



i6 



IS 



MODOC SECTION. 



(Dark gray to bluish black massive limestone poor in fossils ; quite well 

 bedded ; weathering partly smooth and dark colored ; partly rough 

 and pitted and of lighter color ; mostly compact and massive, also of 

 uneven texture ; with numerous calci te seams. 



( Light and dark colored limestone with Stromatopora and Chcetetes; 

 ISO ) contains two layers thinly bedded (fissile). 

 so Compact light yellow sandstone. 



Light and dark colored limestone in layers 10 to 20 feet thick, with 

 Stromatopora and Clustetes. 





Dark colored limestone with Stromatopora and CJiaitetes. 



t Alternating layers (about 10 feet thick) of dark and light gray lime- 

 900 \ stone, finely banded and lined ; weathering brownish gray ; in places 

 ( bearing Chatetes. 



so Compact yellow sandstone. 



ISO Dark and light gray limestone; indistinct bedding. 



jo ( Compact yellow sandstone. 



) Dark and light colored limestone interbedded in layers from 4 to 10 

 250 feet thick. 



270 Light gray siliceous limestone ; very siliceous near base. 



< Alternating beds of dark and light gray limestone; at base 30 feet; 

 ISO j very siliceous limestone ; with cross bedding on weathered surface. 

 3O Compact yellow sandstone. 



f . I Dark and light gray limestone in thick belts of dark, lighter, and 

 "* \ gray colors. 



22.5 Dark dense limestone ; well bedded; bearing fossils. 

 iOO Shaly limestone rich in fossils. 



( Light gray siliceous limestone, with fine lines of bedding; in upper 

 SSO \ portion weathering in almost rectangular fragments; growing 

 ( less siliceous toward the bottom. 



/4O Light gray highly crystalline, saccharoid dolomite ; not siliceous. 



2400 



FIG. 3. Nevada limestone Modoc 

 section. 



