PLATE V. 



Favosites Helderbergi^. 



Page 8. 

 See Plates 4, 6. 

 Fig. 1. An elong-ate subturbinate form, showing larger cells at intervals, most of which are filled with 

 siliceons matter. 



Lower Helderberg group. Clarksville, iV. F. 

 Fig. 2. A broad, turbinate form of the species. 



Lower Helderberg group. Clarksville, N. Y. 

 Fig. 3. A depressed, hemispheric, foi-m where the vertical extent is about one-fifth <u' one-sixth of the 

 diameter. The figure represents the convex upper side of the specimen, fig. 2, plate 4, which 

 is the prevailing form in many localities. 



Lower Helderberg gi-oup. ClarkmlUe, N. Y. 



