Paleotitology of Ihc Ciuriiniali Croup. ^J 



vSub-clasS ZOANTHA K I A . 



Tliis has been split up into varions orders, of vvhicli the 

 Zoa>itf;an'a sdcrodcnnala or Madrcporaria of Nicholson, 

 (Ibid., p. 263,) alone lias representatives in the Cincinnati 

 Group. Of the four sections of the order, aporosa, riigosa, 

 fiDigida and perforata, three are known to occur, the first, 

 second and last. 



Section i. — Madrcporaria aporosa. 



Here the corallum is "composed of more or less compact 

 and solid sclerenchyma, the theca or wall surrounding the 

 visceral chamber being complete and not perforated by aper- 

 tures or pores." (Nicholson, Ibid., p. 264.) Of the numerous 

 genera, only one is found in our section, as below. 



Genus i. — Columnaria, Goldfuss, 1S26. 



"Corallum composite, massive, composed of polygonal, 

 closely-compacted and contiguous corallites, which are united 

 by their walls, but do not possess mural pores. Walls of the 

 corallites not excessively thickened. Septa well developed, 

 typically extending nearly to the center of the visceral cham- 

 ber, and alternately large and small. Tabulce extremely well 

 developed, complete and horizontal. No columella or crtnen- 

 chyma." (Nicholson, Pal. Tabulate Corals, i<S7g, p. 191 ; 

 Goldfuss, Petrefacta Germanise, vol. i, 1826, p. 72; Ibid., 2d 

 ed., vol. I, 1862, p. 67.) Favistclla, Hall, 1847, Pal. of N. Y., 

 vol. I, 1847, p. 275. 



Remarks. — The description above given is that of Nichol- 

 son, and is more comprehensive than the original. It does 

 not, however, diflfer essentially. Tliere can be no doubt 

 about Favistella, Hall, being a synonym, but for comparison 

 it is given below. 



Favistella, Hall, 1847. — "Coral massive, hemispherical or 

 globose, composed of polygonal tubes or cells, which increase 

 by interstitial tubes or by lateral development of tubes upon 

 the margins of the mass ; cells divided transversely by 

 closely arranged diaphragms, and longitudinally by radiating 

 dissepiments ; extremities of the tubes star-form ; rays (dis- 



