EXPLANATION OF PLATE 1. 



Fig. 1. PhyllooraptusCO dubius (Spencer), p. 15. 



Fig. 2. Retiolites venosus (Hall), p. 16. 



Fig. 3. Dendrogkaptus ramosus (Spencer), p. 17. 



3«. Branch enlarged. 

 Fig. 4. Dendrograptus simplex (Spencer), p. 17. 

 Fig. 5, Dendrograptus dawsoni (Spencer), p. 18. 



oa. Branch enlarged. 

 Fig. 6. Dendrograptus frondosus (Spencer), p. 18. 



Ga. Branch enlarged. 

 Fig. 7. Dendrograptus pr^gracilis (Spencer), p. 19. 

 Fig. 8. Dendrograptus spinosus (Spencer), p. 19. 

 Fig. 9. Callograptus niagarensis (Spencer), p. 21. 

 Fig. 10. Callograptus granti (Spencer), p. 21. 



10a. Branch enlarged. 

 Fig. 11. Callograptus multicaulis (Spencer), p. 22. 

 Fig. 12. Callograptus minutus (Spencer), 22. 

 Fig. 13. DiCTYONEMA TENELLUM (Spencer), 26. 



