58 Hershey — Some Western Klamath Stratigraphy. 



Art. IV. — Some Western Klamath Stratigrajyhy • by 

 Oscar H. Hershey. 



In his paper in the May (1905) number of this Journal, Mr. 

 J. S. Diller presents strong evidence in support of his contention 

 that the Bragdon formation in northwestern California is a 

 member of the Carboniferous series. Although I recognize 

 that good paleontologic evidence must be the final arbiter in 

 all discussions such as this concerning the Bragdon sediments, 

 I am as yet not willing to fully accede to his conclusions, but 

 without further field-work am unable to combat them. I 

 make this explanation for the reason that this paper may 

 appear to be an indirect reply to Mr. Diller, whereas it is an 

 endeavor to record some important observations before the 

 vividness of their memory be dulled by time.* 



The objects of this paper are to introduce another formation 

 from the Klamath region, and to show how thrust faulting 

 may have given rise to apparently inexplicable problems in 

 the geology of northern California. 



The folding of the strata characteristic of the southern Kla- 

 math region is largely replaced northward by thrust faulting, 

 breaking the rocks into four great eastwardly tilted fault 

 blocks. Four important members of the fault system are now 

 known. The most westerly was discovered and elucidated by 

 Mr. Diller. It bounds the Klamath province on the southwest 

 and is marked by the abutment of easterly dipping typical 

 Franciscan sediments against the ancient schists of South Fork 

 and Redwood Mountains ; hence, it may be designated the 

 Redwood Mountain fault. The next easterly (second magni- 

 tude faults ignored), which most directly concerns this paper, 

 passes about two miles east of Orleans on the Klamath River, 

 and may be . known as the Orleans fault. The third has its 

 finest development in Eddy gulch, near the Black Bear mine 

 and postoffice and may be known as the Black Bear fault. In 

 this portion of its course it dips easterly at a low angle, prob- 

 ably 15° or 20°, the ancient schists of the Abrams formation 

 having been thrust for possibly five miles over on to the cherty 

 shales considered of Devonian age; but in passing northward 

 and southward it straightens up and becomes nearly or quite 

 vertical, although for scores of miles it continues a prominent 

 break in the strata. The fourth great fault is marked by east- 

 wardly dipping sediments with strong Cretaceous character- 

 istics apparently overhung by Devonian limestones and cherty 



* Writing in the field, in eastern Nevada, without notes, maps or refer- 

 ences, I must ask the reader's indulgence to informalities and to possible 

 slight inaccuracies in figures. 



