328 PALEONTOLOGY 01" OHIO. 



ally broken away. They are too uniform in length, however, for this, 

 and when carefully examined under a magnifier do not show any indi- 

 cations of having been broken. They are generally about half as wide 

 as the stems from which they spring, near 0.06 inch in length, and are 

 arranged at intervals of about their own breadth apart, with rounded 

 sinuses between, thus giving a crenate or serrated appearance to the 

 margins. The pores continue out on these short, lateral divisions ex- 

 actly as on the stems, without interruption. 



Locality and position : Flint Eidge, Ohio. Lower Coal Measures. Prof. Andrews. 



) 



Ptilodictya (Stictopora) carbonaeia, Meek. 



Plate 20, figs. 3a, 6. 



Ptilodictya (Stictopora) carbonaria, Meek (1871) ; Proceed. Acad. Nat. Sci., Philad., 

 XXIII., 160. 



Ramose, branches from their origin generally nearly equaling the 

 breadth of the stems, from which they spring more or less alternately, 

 and at angles generally of about 50° to 60° ; poriferous surface of each 

 side flattened-convex ; lateral margins sharp and smooth ; pores of each 

 side arranged in quincunx, so as to form from about seven to nine lon- 

 gitudinal rows (those of each two adjacent rows alternating), and about 

 the same number may be counted in each oblique row, very nearly or 

 quite circular, and each with prominent margins, so as to appear as if 

 penetrating minute pustules ; intervening spaces usually once and a half 

 to twice the breadth of the pores, and smooth, or without longitudinal 

 ridges or furrows. 



Entire size unknown ; breadth of a medium sized branch, 0.14 inch ; 

 thickness in the .middle, 0.05 inch; number of pores in a space of 0.10 

 inch of each longitudinal row, six, while in the oblique rows about seven 

 may be counted in the same space. 



Among the Silurian species of Stictopora this seems to agree most nearly 

 with S. punctipora, Hall, from the Niagara group, which it nearly resem- 

 bles in its round pores with raised margins, as well as in the number 

 and arrangement of its pores. It differs, however, in having its sharp, 

 lateral margins smooth instead of being striated. A critical comparison 

 of specimens would doubtless show other differences. Its branches are 

 narrower, and the number of its longitudinal rows of pores is also less 

 than in a species from the Corniferous limestone I have named P. Gilberti, 

 which also differs in having longitudinal ridges between the rows of 

 pores. 



locality and position : Newark, Ohio. Coal Measures. 



