548 REPORT UNITED STATES GEOLOGICAL SURVEY. 



extension of the fold of the west side of the Salt River Range. 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 Elver may occupy its 

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

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

 that three anticlinals 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 River will probably throw some 

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

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

 age ; at least nothing more modern apiDearing 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 blue limestones, with fragments of corals, and an indistinct spirifer. 



2. Blue limestones, "weathering light-yellow, with light bands. 



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



4. Dark-blue 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 % 



Platycrlnus % 



Zaplirentis ? 



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



Hemipronites crenistria. 



Spirifer % 



MurcMspnia ? 



Synocladia % 



Productus % 



Euomplialus ? 



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

 the station, the following occur : 



MurcMsonia ? 



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 ? 



Streptorynclms ? 



Ptylodyctia % 



