301 



HELICOTOMA VERTICALIS Ulrich 

 Plate XL1I, Figs. 16, 17 



Helicotoma verticalis Ulrich, 1897, Geol. Minnesota, Pal., vol. iii, pt. 2, 

 p. 1035, pi. Ixii, fig. 69; pi. Ixxiv, figs. 18 and 19. 



Description. This shell, although known only from casts of the in- 

 terior, is so well characterized by the rectangular form of the outer and 

 upper surfaces of the whorls that it should be easily recognized. The 

 whorls are not more than four in number, enlarge rapidly, are strongly 

 convex below and leave a deep and relatively narrow umbilicus. On the 

 under side the cast resembles the shell of Helicotoma planulatoides quite 

 closely, but otherwise the two species are quite different, as the outer side 

 of the whorls in the latter are concave and inclined inward above instead 

 of convex or flat and vertical. 



Occurrence. CHAMBERSBURG LIMESTONE (Tetradium cellulosum 

 bed). Fort Loudon, Franklin County, Pennsylvania. Lowville lime- 

 stone of Kentucky. 



Collection. U. S. National Museum. 



Genus ECCYLIOPTERUS Remele 

 ECCYLIOPTEEUS DISJUNCTUS (Billings) 



Plate XXXV, Figs. 9, 10 



OpMleta ? disjuncta Billings, 1865, Pal. Foss., vol. i, Geol. Surv. Canada, 

 p. 344, text fig. 331a, b. 



Description. Shell about 25 mm. in diameter, consisting of two or 

 three whorls slightly separated from each other and with a strongly 

 elevated, sharp carina. Spire deeply concave; carina located one-third 

 the width from the outer margin. Within the carina there is first a 

 shallow concave band, and then a concave slope into the suture ; without 

 it is a little defined concavity, below which the periphery is uniformly 

 convex. The whorls on the under side vary from uniformly to depressed 

 convex, sometimes becoming flat near the aperture along the median line. 

 Depth and width of whorls about equal, greatest amount of separation 

 of whorls about 4 mm. Surface with rather strong, scale-like striae. 



