CORALS OF THE CLINTON FORMATION. 225 



dimensions, varying in difTerent examples from one to two lines in diam- 

 eter, though usually rather over one line. Mural pores usually in two 

 rows on each of the prismatic faces of the corallites, arranged alternately, 

 or sometimes oppositely, and surrounded by elevated margins. Tabulae 

 usually complete, extending across the visceral chamber without inter- 

 ruption. Septa usually altogether absent, or at most represented by 

 tubercles or short spines. 



The limits of this variable species can perhaps at present be hardly 

 laid down with certainty, but we may safely include under this head 

 those massive forms of Favosites in which the corallites are prismatic, 

 thin-walled, approximately equal in size, about one line, or rather more, 

 in diameter, with two rows of mural pores on each of the prismatic faces 

 of the corallites, these openings being usually arranged alternately. 

 Except in well-preserved specimens, however, it must be admitted that 

 it is by no means always easy to determine examples of F. Gothlandica. 



Position and locality ; Clinton group, Greene county, Ohio. 



Favosites aspera, D'Orbigny. 



Calamopora alveolaris (pars), Goldfuss; Petref. Germ., Vol. I., pi. 26, fig. 16. (Cset. 



exclusis. ) 

 Favosites alveolaris, Lonsdale; Sil. Syst., p. 681, pi. 15 bis, fig. 2. 

 Calamopora alveolaris, Eichwald ; Sil. Syst. in Esthland, p. 198. 

 Favosites alveolaris, Lonsdale ; In Murch. Vern. and Keys. Russia and Ural, Vol. I. 



p. 610. 

 Calamopora alveolaris, Keyserling ; Raise in Petschora, p. 177. 

 Favosites aspera, D'Orbigny; Prodr. de PaMont., Vol. I., p. 49. 

 Favosites aspera (?), McCoy ; Pal. Foss , p. 20. 



Favosites aspera, Edwards and Haime; Pol. Foss. des Terr. Palseoz., p. 234. 

 Favosites aspera, Edwards and Haime ; Brit. Foss. Corals, pi. 60, figs. 3, 3a. 



Corallum massive, sub-hemispheric or pyriform ; corallites polygonal 

 thin-walled, unequal in their dimensions, the larger ones about one line 

 in diameter or a little over. Mural pores placed on the angles of the 

 corallites, instead of on their flat f^ces. Tabulae with six large and well 

 marked sub-iharginal fossulse. 



A small mass from the Clinton formation of Ohio may be referred 

 here, though its state of preservation is such that the characters of the 

 tabulae can not be determined. It can not, therefore, be made out with, 

 accuracy whether the specimen in question is really i^. aspera or the very 

 closely allied, if not identical, i*. alveolaris, Gold. From the inequality 

 15 



