PLATE II A. 



Favosites hemispherica var. a. (subturbinate forms). 



Figs. 1-3. Upper, lateral and basal views of a specimen of this variety, showing the small cells 



peculiar to this form. 

 Figs. 4, 5. Two views of another specimen of similar character, but having the upper part e.\tended 



into a dome-shaped elevation. 

 Fig. 0. Lateral view of another individual where the upper part is elevated into a conical form. 

 Fig. 7. Longitudinal section of a highly dome-.'^haped specimen, showing the diverging character 



of the cells in their upward extension. From the Upper Helderberg Limestone 



State of New York, and Falls ot the Ohio. 



