EOCENE FACIES OF THE TEJON. 247 



division "2?," now known as the Tejon formation, Mr Conrad asserting 

 that it is Eocene and Mr Gabb as strenuously maintaining its Cretaceous 

 age* On the one hand, the unquestionable fact that a number of the 

 fossils are identical or closely related with species that elsewhere charac- 

 terize the Eocene was regarded as proof of its Tertiary age ; while on the 

 other hand, the presence of an ammonite (Ammonites jugalis) and the 

 apparently close faunal and stratigraphic connection with the Cretaceous 

 beds beneath were believed to prove its Cretaceous age. According to 

 Mr Gabb's f statement in one of his controversial articles, 23 species of 

 the 107 in division B are found in the underlying beds. When his 

 list of common species is critically examined, however, it is seen that, 

 with the exception of the Ammonites and perhaps two or three others, they 

 all belong to genera that have lived from the Cretaceous or earlier to the 

 1 tresent time without undergoing much change. Professor Angelo Heil- 

 prin \ has given a careful review of all the published evidence bearing 

 on this question, and in preparing it he has studied a large part of Mr 

 Gabb's original collections of California fossils. His article is a strong 

 argument for the Eocene age of the Tejon and incidentally it throws 

 considerable doubt on the accuracy of Mr Gabb's statements concerning 

 the species that occur in both the Chico and the Tejon. 



Professor Jules Marcou§ and Dr C. A. White || have also referred the 

 Tejon, or division B, to the Eocene, and this view is now generally 

 accepted. While admitting its Tertiary age, both Dr White ^[ and Dr G. 

 F. Becker,** after studying the subject in the field, have stated their 

 belief that in southern California the Tejon, is only the upper part of an 

 unbroken series, the Chico-Tejon, in which the sedimentation as well as 

 the life was continuous from the Cretaceous into the Tertiary. 



In the second volume of the Paleontology of California, published in 

 1869, Professor Whitney ff again summarized Mr Gabb's latest views on 

 the classification of the Cretaceous. Division B is named the Tejon 

 and considered to be the probable equivalent of the Maestricht beds. 

 Division ^1 is separated into three groups : the Martinez group, which 

 is doubtfully separated from the one next below ; the Chico group, which 



♦Conrad's articles arc in Am. Jour. Conch., vol. i, 18G5, pp. 3G2-305; vol. ii, 1866, pp. 97-100, and 

 Am. Jour. Sci., vol. xliv, 1867, pp. 376-377. Gabb's replies may lie found in Am. Jour. Conch., vol. ii, 

 pp. 87-92; Am. Jour. Sci., vol. xliv, 'pp. 226-229, and Proc. Cal. Acad. Nat. Sci., vol. iii, 1867, pp. 301- 

 306. 



fProc. Cal. Acad. Nat. Sci., vol. iii, 1867, p. 302. 



JProc. Acad. Nat. Sci. Phi la., 1882, pp. 195-214 ; Contributions to Tertiary Geol. and Paleont. of flic 

 United States, 1884, pp. 102-117. 



g Bull. Soc. Geol. de France, tome xi, 1883, pp. 417-435. 



|| Bull. 15, U. S. Geol. Survey, 1S85, pp. 11-17; Bull. 51, 1889, pp. 11-14; Bull. 82,1891, p. 193. 



U See references just given. 



** Bull. 19, U. S. Geol. Surv., 1885. 



+t Pages xiii and xiv. 



