PLATE XXII 



PAGE 



Fig. 12. Ammonites jugalis, from tlie Martinez Group at Benicia. 133 



12 a. Cross section of body whorl. 



12 J. Septum from same specimen. 



Fig. 13. A specimen of the same from Martinez. 



13 a. Front view of same. 



Fig. 14. A. Whitneyii. 134 



14 a. Front view of the same. 

 14?>. Septum of the same. 



