U4 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th See. 



PLATE 11. 



(Unless otherwise stated, all figures are natural size.) 



PAGE 



V enericardia planicosta ionensis Waring. 96 



Fig. 1. Right valve, XK-- From Umpqua formation (Upper Tejon), 

 Umpqua Valley, Oregon. This same variety is found in 

 the lone at Merced F'alls, California. L. S. J. U. Pal. 

 Coll. 



Fig 2 Young specimen showing change in ribbing. Same locality. 

 L. S. J. U. Pal. Coll. 



FencricardUi planicostii hornii Gabb. 95 



Fig. 3. Exterior of right valve, Xi!^. 



Fig. 4. Anterior view of both valves, XK', from Olequa formation, 



Little Falls, Washington. Lower margin of valves 



water-worn. 

 Fig. 5. Young specimen. 



This species is introduced here for comparison. It is character- 

 istic of the Chehalis and Olequa formations (Tejon Group), Wash- 

 ington, and of the Tejon of California. 



V enericardia planicosta venturcnsis, new subspecies. 80 



Fig. 6. Exterior of left valve, X''^- 

 Fig. 7. Anterior view of both valves, XJ^- 

 F"ig. 8. Inside of left valve, X^, showing hinge. 

 Fig. 9. Inside of right valve. X/^, showing hinge and muscle im- 

 pressions. 



This species is characteristic of the Martinez formation. 



All four specimens are from Loc. 4, L. S. J. U. Pal. Coll. 



