260 University of California Publications in Geology [Vol. 7 



so-called "Cretaceous B" beds of Gabb was still undecided and 

 on this account many points in his discussion are somewhat con- 

 fused. 



Lindgren and Turner 4 in the Marysville Polio described the 

 relations of the sedimentary beds to the central igneous core, 

 divided the sedimentary beds into two formations, the lone and 

 the Tejon, recognized the age of the Tejon as Eocene, and the 

 lone as Miocene. This description is as follows : 



"Between the exterior mud-flows and the massive core, and 

 strongly contrasting with them, there often occur a series of 

 smooth, rounded hills forming a frequently interrupted ring 

 a mile or less in width. These hills are not volcanic but consist 

 of a series of sandstones (usually soft), white or dark clays and 

 gravelly beds. The beds are very much disturbed and dip at 

 all angles and in all directions. As a rule, however, they dip 

 away from the central core, and when near it stand at high 

 angles, sometimes vertical. At the immediate contact with the 

 massive volcanic rocks these sediments are usually hardened. No 

 volcanic detritus of the same rocks of which the Buttes are 

 made up is found in them, and it may be regarded as certain that 

 they were laid down before the period of volcanic activity. The 

 oldest of the formations belongs to the Tejon formation (Eocene) ; 

 it has thus far been identified only in the sedimentary area 

 northeast of the village of West Butte. It is here composed of 

 greenish sandstone and shales, adjoining the volcanic masses 

 and dipping at high angles east or west. A thickness of several 

 hundred feet of sediments is exposed. Some of the beds contain 

 abundant marine fossils, characteristic of the Tejon among which 

 a small coral (Trochosmilia striata Gabb) is most abundant. 

 Cardita planicosta, a form eminently characteristic of the Tejon 

 is also found. Overlying these beds are light-colored, soft sand- 

 stones and clays, dipping west at an angle of about 20°, which 

 have been referred to the lone formation. The other sedimentary 

 areas consist largely, if not entirely, of these soft light-colored 

 beds." Lindgren 5 in a recent publication summarizes the dis- 



* Lindgren, W., and Turner, H. W., Marysville Folio, U. S. Geol. Surv. 

 Folio 17, April, 1895. 



s Lindgren, W., The Tertiary Gravels of the Sierra Nevada of Cali- 

 fornia, Professional Paper, U. S. Geol. Surv., No. 73, pp. 23-25; 1911. 



