Upper Helderherg Group. 



173 



Fenestella ^qualis, n. sp. 

 Width of branches from .25 to .35 mm.; on uon-celluliferous side 

 angular, slightly carniated ; dissepiments, varying from two-thirds of 

 to equal the width of the branches ; fenestrules usually subquadran- 

 gular, length .75 mm.; width from .60 to .75 mm.; cells in two 

 ranges, apertures circular, space between ranges elevated, angular no- 

 dose. 



Locality — Clarence Hollow, N Y. 



Fenestella luxulata, 11. sp. 

 Infundibuliform ; width of branches from .25 to .50 mm.; dissepi- 

 ments equal in width to the branches, generally on the non-cellulif- 

 erous side a semicircular ridge extending on the branches and at the 

 middle of the dissepiments a strong oblique spine, projecting over the 

 fenestrules; fenestrules variable, frequently oval, width equal to that 

 of the branches ; length one and one-half times the width; cells in 

 two ranges, apertures sometimes oblique, 22 in 5 mm., space between 

 ranges carinated, carinse thin, elevated from .35 to .50 mm., then ex- 

 panding, the expansions .20 mm. wide. 



Locality — Falls of the Ohio river. 



Fenestella latijunctura, 7i sp. 

 Branches on non-celluliferous side very irregular, width from 1 to 

 1.50 mm., nodose, nodes irregular in size and appearance, sometimes 

 one mm. high, frequently oblique, sometimes there is a thin sharp 

 carina with elevations; dissepiments one mm. in width, fenestrules 

 oval, width equal to that of the branches, and from one-half to two- 

 thirds the length ; cells in two ranges, apertures circular, 18 in 5 mm. 

 middle of branch carinated, one mm. in height at one-third the dis- 

 tance above the branch; expanded, width of expansion .25 mm., then 

 contracting, the expanded portion having on its margin nodes equal 

 in number to the apertures. 



Locality — Falls of the Ohio river. 



Fenestella bi imbricata, n. sp. 



Width of branches, 34 mm. ; on non-celluliferous side very irregular; 

 dissepiments, one mm. or more in width, on non-celluliferoous side, 

 the summit elevated, continuing on the branches, forming a promi- 

 nent semicircular elevation around the lower portion of fenestrule; 

 fenestrules nec-rly circular, diameter .50 mm., sometimes subtriangu- 

 lar , cells in two ranges ; apertures circular, 22 in the space of 5 

 mm. ; carina attaining a height of .50 mm., then abruptly expand- 



