84 THE OLD RED AND CARBONIFEROUS PERIOD. CHAP. 



Diagram XX. i. Tooth of Orodus cinctus (Ag.), seen laterally. Bristol. 

 2. Tooth of Helodus gibberulus (Ag.), looking on the crown. 3. Tooth of 



Cochliodus contortus (Ag.). The perfect Irish specimen is in the collection of the 

 Earl of Enniskillen. 4. Tooth of Psammodus porosus (Ag.}. Bristol. 5. Dorsal 

 spine of Ctenacanthus. Bristol. 



Diagram XXI. Mountain Limestone (fossils reduced). 



j. Lithostrotion basaltiforme. Phil. 2. One of the cells. 3. Chsetites septosus. 

 Flem. 4. Shews the septa across the vertical tubes. 5. Amplexus Sowerbii. 



Phil. 6. Syringopora geniculata. Phil. 7. Actinocrinus tessellatus. Phil. 



8. Phillipsia seminifera. Phil. 9. Terebratula sacculus. Sow. 10. Spirifera 



cuspidata. Sow. n. Rhynchonella pleurodon. Phil. 12. Producta punctata. Sow. 

 13. Pleurorhynchus minax. Phil. 14. Sanguinolaria sulcata. Phil. 15. Aviculo- 

 pecten granosus. Sow. 16. Murchisonia rugifera. Phil. if. Pleurotomaria 



biserrata. Phil. 18. Acroculia vetusta. Sow. 19. Bellerophon apertus. Sow. 



20. Nautilus dorsalis. Phil. 



