PLATE I 



LYKINS FOSSILS 



Myalina perattenuata (p. 6) 



Fig. 1. A large right valve referred to this species. 



2. A left valve of more nearly the average size. 



Lykins formation, Heygood Canyon, Colorado (lot 3266). 



Myalina tcyomingensls (p. 5) 



3. A large left valve. 



Lykins formation, Heygood Canyon, Colorado (lot 3265). 



Alula sQuamulifera (p. 4) 



4. Side view of an internal mold of a right valve. 



4a. A view obliquely down on the cardinal margin of the same specimen, 

 showing the impression left by the linear anterior and posterior 

 teeth, x 2. 



5. Squeeze of a right valve showing the surface characters. 



5a. Same, x 2. Even with this magnification, the fine squamose character 

 of the costee cannot be shown. 

 Lykins formation, Heygood Canyon, Colorado (lot 3266). 



Aluta gilberti? (p. 5) 



6. Side view of a doubtfully identified right valve. 

 Lykins formation, Perry Park, Colorado (lot 3263). 



Murchisonia buttersi (p. 6) 



7. Side view of a squeeze made from the type specimen. 



8. Another squeeze made from the same specimen, x 2. 

 Lykins formation, Heygood Canyon, Colorado (lot 3264). 



