EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA 5 I 



mopora fibrosa Goldfuss with which Roemer identified his specimens 

 from Perry county, Tenn. is a monticuliporoid or at all events not a Hinclia, 

 but Roemer's fossils were Hindias and when this generic name was proposed 

 by Duncan it was to a species which so far as all investigations show is in 

 no wise distinct from Roemer's. The Astylospongia i n o r n a t a 

 Hall from the New Scotland and Port Ewen beds of the New York Hel- 

 darbergian is the same organism and if scruples of any kind should prevent 

 the use of the term fibrosa then Hall's specific name would have priority 

 over Duncan's. 



Rauff has brought together as this species ball-shaped sponges from a 

 variety of geological horizons from the Trenton limestone upward to the 

 Helderbergian. Hinde has shown the Helderberg forms from Dalhousie, 

 New York and Tennessee to be of one species, but at present we have no 

 reliable evidence that this species occurs below or above that horizon. 



These bodies are extremely abundant at Dalhousie. 



Horizon. Nos. i, 8, 9. 



Supposed marine algae 



Plate 11, figures 15, 1 1 



Some of the layers at Dalhousie abound in bunches or tangles of 

 fine black threads often branching from a central stock and sometimes 

 associated with heavier stipes. 



The chitinous matter of these bodies is thin and unsubstantial, too 

 much so for graptolites nor do they show traces of thecae. They present 

 certain suggestions of the Gorgonict; were they gorgonians there should be 

 some evidence of a calcareous layer surrounding an interior chitinous axis 

 but there is no distinction of parts in these frail bodies, and even though 

 we might conceive the calcareous matter dissolved out jet the evident flexi- 

 bility of these films, shown by the forms they have assumed under drifting, 

 indicates an entire absence of the rigidity which characterizes the Gorgonia 

 stem. With dissolution of the calcareous matter coralline algae might 

 leave such tenuous brown films, and some of the recent Dasycladaceae 

 would with the abstraction of their lime present such an aspect with the 

 ramuli in verticils about a jointed shaft. These bodies do not distinctly 

 show the jointing of the shaft though there are scars along the stems which 

 indicate the attachment of deciduous branchlets. Some show clearly the 

 arrangement of the branchlets in whorls. The presence of thicker and 

 larger stocks anion? these drifted bodies seems also to suggest an algous 

 nature. We have before made reference to a somewhat similar plant 

 organism occurring in the St Alban beds and have quoted the judgment of 

 Mr David White as to its probable nature. Here as there we may be 

 dealing with objects ancestrally lepidodendroid but still unrevealed. 



Horizon. No. 12. 



