PLaTE XXVIII 
Unio vetustus Meek. Bear River beds of the Cretaceous series. 
Fic. 1. Right side view of probably a male specimen. 
Fic. 2. Dorsal view of the same specimen. 
Fic. 3. Interior view of a left valve. 
Unio belliplicatus Meek. Bear River beds of the Cretaceous series. 
Fic. 4. Left side view of probably a male specimen. 
Fic. 5. Left side view of probably a female specimen. 
Fic. 6. Dorsal view of a left valve, showing beak sculpture. 
