Upper Helderberg Group. 429 



AULACOPHYLLUM TRIPINNATUM, n. Sp.jP/^V/c ft>/X. 



Oorallum simple, turbinate, short, some individuals gradually, 

 others rapidly expanding; diameter of calix 20 mm.; number of lam- 

 ellae 80, alternate ones much larger than the others ; their arrangement 

 is as follows, on the posterior side is one lamella extending from the 

 margin to the bottom of the cup, a little to one side of the center, 

 those adjacent it on the left side converge to it, those on the right 

 side are parallel with it ; on the right side is a deep fossette, on the 

 left side a less conspicuous one, a sharp depression connecting the two ; 

 the lamellae converging to the fosse ttes and connecting depression, not 

 reaching the center of the calix; anterior to the depression is an 

 oblique space 10 mm. wide and of about the same height, essentially 

 smooth, formed by the coalescing of the lamellae. 



Formation and locality. Corniferous limestone, Falls of the Ohio. 



^ AULACOPHYLLUM TRISCUL ACTUM, 71. Sp. /V*<£. V,'* J,r-f . 



Corallum turbinate, irregularly expanding, exterior with numerous 

 constrictions caused by intermittment growth ; internal costae sharp, 

 prominent ; height of corallum 40 mm. ; calix 35 mm. in diameter, sub- 

 quadrangular in outline,depth 20 mm., sides abruptly sloping to the cen- 

 ter. There are three f ossettes,one wide and deep extending from the cen- 

 ter of the calix to the anterior margin, the others, not so strong, but still 

 conspicuous, are situated at right angles to the principal one ; lamellae 

 about 112, alternate ones much larger than the others, very sharp and 

 prominent, converging to the fossettes, and on the posterior side to a 

 line in continuation of the principal fossette ; a few reach the center of 

 the calix and are there twisted and elevated forming a false columella. 



Formation and locality. Corniferous limestone, Falls of the Ohio. 



AULACOPHYLLUM POCULUM, 71. Sp.fl^J, Vj» / J, /«f ,V; A^T 



Corallum simple, subcylindrical, short, attached portion or the base 

 large, frequently equal to the diameter of the corallum ; height of coral- 

 lum 20 mm.; diameter of calix 20 mm., depth from 8 to 12 mm., 

 sides sloping abruptly, leaving at the bottom a concave space 3 mm. 

 wide ; fossette situated posteriorly, extending from concave space at 

 the bottom of the calix to the margin ; number of lamellae from 80 to 

 90, alternating in size, the smaller ones scarcely more than rudiment- 

 ary. The lamellae near the fossette converge to it, the others to the 

 center, a few extending upon the concave tabula and coalescing with it. 



Formation and locality. Corniferous limestone, Falls of the Ohio. 



AULACOPHYLLUM BILATERALE, 11. Sp. ?/X-7. Via J~ 



Corallum simple, turbinate, subquadrilateral, straight or slightly 

 curved, the attached portion usually broad, sometimes equal to the 



