196 TABULATE CORALS. 



Obs. Having given an account of this species in describing 

 the structure of the genus Columnaria, I have little to add to 

 the above specific diagnosis. I entertain no doubt at all that 

 the specimens described and figured by Goldfuss (Petref. Germ., 

 PI. XXIV., fig. 7) are really the present form so well known 

 to American palaeontologists under the name of Favistella stel- 

 lata, Hall and that they are quite different to the species 

 described by Hall, M'Coy, and others under the name of C, 

 alveolata. Not only do Goldfuss's figures show the extension 

 of the septa to near the axis of the visceral chamber in the 

 clearest possible manner, but his examples were actually col- 

 lected on the shores of Seneca Lake, in the State of New 

 York, where the Lower Silurian Rocks do not occur in place, 

 so that they were doubtless derived from a travelled boulder 

 originally belonging to the Hudson River formation. 



I should be inclined to think that a re-examination of the 

 specimens upon which Mr Billings founded his Columnaria 

 rigida (Geol. Surv. of Canada, Rep. of Prog, for 1857, p. 167, 

 1858) would show that these are really the same as C. alveola fa. 

 Mr Billings himself states that the principal distinction between 

 the two is, that in C. rigida the septa do not quite reach the 

 centre of the visceral chamber, whereas in C. alveolata (which 

 he calls Favistella stellata, Hall) the septa not only reach the 

 centre, but are often " so strongly developed there as to pro- 

 duce by their junction the appearance of a pseudo-columella." 

 This last-mentioned appearance is one that I have never seen, 

 while it is quite common for the septa of C. alveolata to fall 

 short of the centre of the visceral chamber, as indeed the 

 most of them almost always do ; so that I hardly think C. 

 rigida, Bill., can be retained as a distinct species. 



Formation and Locality. Abundant in the Cincinnati group 

 (Hudson River Group) of Canada and the United States. Dr 

 Rominger (Foss. Cor. of Michigan, p. 90) quotes it also from 

 the Niagara Group (Upper Silurian). 



