112 University of California Publications in Geology [Vol. 10 



which R. W. Pack of the United States Geological Survey, and later 

 R. H. Stoner of the University of California, secured the interesting 

 mammalian remains described in 1915. 



For important mammalian material secured, and for additional 

 data concerning the sequence of formations and occurrence of mam- 

 malian remains, the writer is much indebted to the party visiting 

 the Tejon Hills area in 1915. Reports on the geologic occurrence 

 furnished by members of the 1915 party are given in full in the dis- 

 cussion of stratigraphic position following. 



STRATIGRAPHIC POSITION OF MAMMAL-BEARING 

 CHANAC FORMATION IN THE TEJON HILLS 



As noted in the earlier publication- on the Tejon Hills fauna, 

 difference of opinion has existed concerning the formation sequence 

 and the age of the deposits containing mammalian remains obtained 

 in this area. The geologic section has not been easily understood, 

 and age determination could not readily be made without fuller in- 

 formation as to invertebrate faunal sequence of the Pacific Coast 

 Province than was at hand at the time of the first examination of the 

 Tejon Hills region. In the earlier studies there seemed good reason 

 for considering that remains of land mammals were found in strata 

 containing a marine invertebrate fauna comparable to that of beds 

 of the Temblor Range referred to Lower Miocene. Other opinion sug- 

 gested tentatively the "Santa Margarita" or late Miocene age of the 

 mammal-bearing formation. 



With the evidence available at the time of publication of the 

 earlier paper 3 the writer concluded that intensive study of the in- 

 vertebrate fauna of the Tejon Hills would be necessary before a fully 

 satisfactory correlation with other marine Tertiary formations of the 

 San Joaquin Valley could be made, and expressed the view that 

 faunas of both "Santa Margarita" and "Temblor" stages might be 

 represented in the section. 



As is stated in the reports by Dr. Buwalda and Dr. Clark given 

 below, the work of the 1915 party points toward the existence of three 

 divisions or three formations in the geologic section of the Tejon Hills. 

 The divisions reported are: (1) marine "Temblor" or Monterey, 

 generally considered as Lower Miocene; (2) marine "Santa Mar- 



2 Merriam, J. C, op. (At., 1915. 



s Merriam, J. C, op. ait., pp. 284 and 285, 1915. 



