PLATE XXX 



PAGE 



Fig. 1. STROMATOPORA CONSTELLATA Hall 221 



Type C. View of surface showing mamelons and astorhizae. Helder- 

 berg formation, Keyser member, Devil's Backbone, Stromato- 

 pora bed. 



Fig. 2. SYRIXGOSTROMA CENTRQTUM Girty 225 



View of surface showing numerous small mamelons. Helder- 

 berg formation, Keyser member, Warrior Mountain, Allegany 

 County. 



21 



