506 NON-MAKINE FOSSIL MOLLUSCA. 



PLATE 10. LARAMIE. 

 OSTREA GLABRA Meek & Hayden. (Page 421.) 



FIG. 1. Exterior view of an upper valve, from the valley of tlie South Platte, Colorado. 

 FIG. 2. Interior view of the same. 



FIG. 3. Lower valve of the type of the variety 0. insecuris White; exterior view. 

 FIG. 4. Interior view of the same. 

 FIG. 5. Type specimen of variety O. arvuatilia Meek. 

 (All natural size.) 



