PLATE XXVIII 



PAGE 



Figs. 1, 2. STROMATOPORA CONSTELLATA Hall 221 



Type C. Tangential and radial sections (thin sections). Showing 

 very large and intricately branched astorhizae. Helderberg 

 formation, Keyser member, Cumberland. 



Figs. 3, 4. SYRINGOSTROMA BARRETTI Girty 224 



3. Section obliquely tangential. X 10. 



4. Section obliquely radial. X 10. Branch of Cladopora rectilineata 



(Simpson) at edge. 



Helderberg formation, Keyser member, Cookerly, Stromato- 

 pora bed. 



Figs. 5, 6. SYRINGOSTROMA CENTROTUM Girty 225 



5. 6. Tangential and radial sections. X 10. Helderberg formation, 



base of Keyser member, Warrior Mountain, Allegany County. 



19 



