PLATE I. 



Fig. 1. STROMATOPORA OSTIOLATA, Nich. A fragment of the natural size, from the 



Guelph Formation. Introduced for comparison. 

 la. Portion of the same, enlarged, showing the oscula on the surface. 



Fig. 2. STROMATOPORA TUBERCULATA, Nich. A fragment of the natural size. (p. 14.) 

 2a. Section of a portion of the same, enlarged. 



Fig. 3. STROMATOPORA GRANULATA, Nich. A fragment of the natural size. (p. 16.) 

 3a. Section of a portion of the same, enlarged. 



Fig. 4. STROMATOPORA MAMMILLATA, Nich. A fragment of the natural size. (p. 17.) 



