PLATE IV. 
Favosites Helderbergi.®. 
Page 8. 
See Plates 5, 6. 
Fig. 1. The lower side of a highly conical form which preserves the epitheca in an unusual degree of 
perfection. 
Lower Helderberg group. Clarksville, N. Y. 
Fig. 2. The lower side of a more explanate form, from which the epitheca has been nearly removed by 
weathering or solution, leaving the silicified cell walls and some of the septa. Some of the 
cells are entirely filled with siliceous matter and others are free. 
Lower Helderberg group. Clarksville, N. Y. 
