PLATE 8. 
Fig. 1. 64. 1. PuHytopsis TUBULOSUM. (Pag. 38.) 
1. A fragment of rock, showing several stems of this fossil, with their anastomosing branches. 
1 a. A similar vertical section, where the stems have been divided, showing that they were originally hollow. 
16. A bulb of stony matter, embraced by the stems or rootlets of this fossil. The stems apparently proceed 
from such a bulb or root; as the radicles converge below and diverge above, as represented in the figure. 
1c. A horizontal section, presenting the ends of several stems, most of which are less than the ordinary size. 
The rock is discolored for some distance around these stems, as if deprived of its coloring matter by the 
carbonaceous character of the fossil. 
1d. A horizontal section of stems larger than the usual size : these stems are cellular, with apparent lon- 
gitudinal dissepiments in two of the four presented in the figure. 
1 e. A horizontal or transverse section of the stems, showing a concretionary arrangement of the calcareous 
matter around them, which, on weathering, presents the appearance here represented. 
