Diller and Schuchert — Devonian Rocks in California. 42 L 



ring respectively in the Eureka and White Pine Mining Dis- 

 tricts of Nevada. The California specimens consist of sepa- 

 rated and distorted valves. 



Correlation with other regions. 



The corals of the Devonian limestone of Shasta county are 

 believed to indicate the lower portion of the middle Devonian 

 or approximately the Corniferous terrane as developed in New 

 York, Kentucky, Michigan, and Ontario. It should be borne 

 in mind, however, that since many species of corals have a 

 great geographical and considerable vertical distribution, great 

 reliance cannot always be placed on them for limited correla- 

 tion. Mr. Walcott* has identified twenty-five species of this 

 class in the Devonian of Nevada. Some of them hold a dif- 

 ferent stratigraphic position from the same species in eastern 

 America. He writes : " Among the corals, Cladopora pulchra, 

 Syringopora hisingeri, and Cyathophyllum corniculum, of 

 the great Corniferous coral reef of the east, occur at the upper 

 horizon, and Syringopora perelegans, of the same formation 

 in New York, ranges throughout the group in Nevada."f 



The fossils from near Gazelle, in Siskiyou county, here con- 

 sidered as of later or younger age than those of the Shasta 

 county limestone agree, in a few cases specifically with the 

 Devonian fauna of the White Pine Mining District in Nevada. 

 Two species, Acervularia pentagona and Diphyphylhcm fas- 

 cicidum.., certainly occur in both regions, while l J entamerus 

 comis or P. lotis also seems to be present. A single small 

 Bellerophon was found with these species, and may prove to 

 be a young specimen of B. peiplexa Walcott, as found in the 

 Eureka District of Nevada. The Devonian strata of the 

 White Pine Mining: District are silver-bearing, while the 

 middle Devonian horizons of Shasta and Siskiyou counties are 

 a part of the Auriferous series of California. 



List of species known to occur in the Devonian of California. 



( Shasta County. ) 



12 3 4 5 6 



lavosites clelandi Davis ? . . x 



" canadensis Billings x _. .. x 



" species No. 1_ .. _. .. .. -. x 



" " No. 2 ... .. __ __ .. ... x 



" " No.3 ' .. .. x 



No. 4... .. .. .. .. .- x 



Cyathophyllum robustum Hall, 1876? __ .. .. x 



branching form No. 1 . . ? x 



" •' " No. 2 x .... ? x 



*Mono. viii, U. S. Geol. Survey, pp. 100-106, 1884. 

 f Op. cit., p. 4. 



