PLATE 6. 



Page. 



Fig-. 1. Glyclmebis berthoudi 299 



a. Left-side view ; natural size. 



h. Dorsal view of the same example. 



Fig. 2. Babbatia coalvillensis 286 



a. Exterior view ; left valve ; natural size. 



b. Interior view, showing hinge, the middle portion of which is 



imperfect. Both are partial restorations. 



Fig. 3. Plicattjla hydbotheca 279 



a. Natural cast in sandstone of the deeper valve ; natural size. 

 i. External view of the upper or flat valve. 



Fig. 4. Mactra? hoemesii 295 



a. Bight valve ; natural size. 

 6. Left valve. 



c. Side view ; type-specimen. 



Fig. 5, a and & ; represent pro hahly the same species ; from near 

 CaQon City, Colo. 



Fig. 6. Cabyophyllia johannis 274 



a. Side view ; enlarged two diameters. 

 &. Calycular view of the same. 



Fig. 7. Cabtophyllia? egebia 275 



a. Side view ; enlarged two diameters. 



6. Vertical view of another example, broken across just below 

 the calyx. 



