PLA.TE I. 



Page. 

 FlG. 1. OSTREA LUGUBIIIS 123 



1 a. Under valve attached to a piece of rock, and showing the inside, -with the muscular impression. 



1 6. Outside view of an upper valve of same. 



1 c. Outside view of an under valve, showing the scar of attachment, which is unusually small. 



1 d. Inside view of another specimen. 



Fir,. 2. OSTREA UXIFORMIS 124 



2 a. Inside view of an under valve. 

 2 6. Outside of same. 



2 c. Lateral view of same. 



FlG. 3. EXOGYRA COLUMBEI.I.A f. - 124 



3 a. Outside of under valve, from a wax cast taken in a mould left in the matrix. 

 3 6. An internal cast of an under valve. 



3 c. Side view of same. 



3d. An internal cast left in the rock, of the inside of the upper valve. 

 FIG. 4. ANOMIA NITIDA 125 



4 a. View of an upper valve, with only a portion of the shell attached to the cast. 



4 b. An outline side view of the same. 



FlG. 5. Pl.ICATULA ARKXAKIA !'<<> 



5 a. An internal cast of the under valve. 

 56. Outside of the upper valve. 



5 c. A side view of same. 



FlG. 6. IKOCKRAMUS FRAGII.I8 127 



FIG. 7. CAPROTINA BIOORNIS - 126 



7 a. A view of one of the valves. 



7 6. The two valves together. 



FlG. 8. CVPRIMERIA? CRASSA 128 



8 a. Outside of a right valve. 



S 6. An internal cast of the same valve, showing the muscular and pallial impressions and a cast of the 



hinge. 



8 c. Hinge of the right valve. 

 8 <?. An anterior view. 



