PLATE XXXV. 



Favosites placenta. 



FavosiU's placenta Rom'mger. Geological Survey of Michigan : Palseoiitology. [Iiied.] 



Figs. 1 and 2. Lateral and summit views of a young colony having a subturbinate form. 



Figs. 3 and 4. Lateral and summit views of an irregularly growing subturbinate form. 



Fig. 5. A larger, depressed and more spreading form. 



Fig. 6. An extremely expanded foim, showing some inequality in the size of the cells. 



Fig. 7. A lateral view of the specimen fig. C, showing the elevation and inequalities of the surface. 



Fig. 8. An enlargement of the open cells, from the specimen fig. 6. 



Fig. 9. The cell-apertures, from a polished surface of the specimen fig. G. 



Fig. 10. An enlargement of ihe cell-apertures, from the base of the .specimen fig. 3, showing them 

 closed by opercute. 



Fig. 11. A farther enlargement of the cells of fig. 3, showing the opercula;. 



Fig. 12. An enlargement of a vertical section, from the specimen fig 6, showing the partial dia- 

 phragms and a few large pores. Hamilton group, at numerous localities in Western 

 New York, and at Widder and Bosanquet, Ontario. 



