548 KEPORT UNITED STATES GEOLOGICAL SUEVEY. 



extension of tlie fold of the west side of tlie Salt Eiver Eange. It was 

 impossible to determine from the station whether or not the sharp east- 

 ern anticlinal extends northward or not ; but the topography indicates 

 that if it does it becomes gentler. John Day's Eiver may occupy its 

 axis. The canon of Snake Eiver is only thirteen miles north of Sta- 

 tion 57. Professor Bradley passed through this canon in 1872, and says 

 that three anticltnals are crossed, in the third of which (the most west- 

 ern) there is considerable displacement. The investigations of Mr. 

 St. John in the region north of Snake Eiver wdl probably throw some 

 light on the structure of the northern portion of the range. AU the 

 rocks exposed in this portion of the range are probably of Carboniferous 

 age ; at least nothing more modern appearing north of Glacier Creek as 

 far as Station 57. 



The sequence of the rocks at Station 57 is as follows, beginning at the 

 west and going down : 



Section No. 14. 



1. Massive bhie limestones, Avith. fragments of corals, and an indistinct spirifer. 



2. Blue limestones, weathering liglit-yellow, with. Mglit bands. 



3. Blue and yellowisli limestones, in rather thin bands that are highly fossiliferous. 



4. Dark-bhie limestones. 



5. Yellowish limestones, with perhaps bands of quartzite. These beds were seen only 



from, a distance. 



Layer No. 4 or No. 5 may possibly be the equivalent of the fossilifer- 

 ous horizon of Virginia Peak. Layer No. 3 represents the limestones 

 outcropping on the station, about 150 feet in all, and containing fossils 

 at five horizons or layers, as follows : 



At the top, on layer 1, we have — 



Hemipronites crenistria. 



Euomplialus ? 



Platycrinus ? 



Zaplirentis 1 



In layer No. 2, 50 feet lower down, occur — 



Heniipronites crenistria. 



Spirifer 



Murchisonia 

 Synocladia — 

 Productus — 



Euomphalus *? 



In layer No. 3, 40 feet below No. 2 and 90 feet below the summit of 

 the station, the following occur : 



Murchisonia ? 



Euomplialus ? 



And a few feet below them — 



Spirifer ? 



Prcetus ? 



Streptorynclius ? 



In layer No. 4, 60 feet below No. 3 and 150 feet below the station, are 

 the following : ' 



Productus ? 



StreptoryncJms — *? 



Pfylodyctia ? 



