Vol. 5] 



Jordan. — The Fossil Fishes of California. 



109 



tained by Dr. Bowers on Carrizo Creek, San Diego County, near 

 the Mexican line. This tooth is flat, narrowly triangular, and 

 nearly erect. 



14. Isurus tumulus Agassiz. 



(OxyrMna tumula Agassiz, 1. c. p. 275; Ocoya Creek.) 



Many specimens of Isurus, large and small, seem to belong tc 

 a species of Isurus distinct from Isurus planus. The scanty de- 

 scription of Isurus tumulus, characterized by "the extraordinary 



Fig. 10. Isurus tumulus (Agassiz). Miocene of Kern Comity, California. 



thickness of the root of the tooth," seems to apply to this form. 

 We have upward of 100 specimens obtained by Mr. Anderson 

 from the Miocene of Barker Ranch, and especially from the Mio- 

 cene four miles east of Oil City, with large examples from near 

 Santa Ana. In some of these the tooth is two and one-half inches 

 in height, a size enormous for an Isurus. The crown is rather 

 slender, narrowly triangular sometimes, somewhat flexuous, the 

 outer teeth broadly triangular, all the teeth much more convex in 

 section than in Isurus planus, and less flat. The base is thicker, 

 usually broadly lunate. None of the teeth are so strongly hooked 



