DESCRIPTIONS OF SPECIES 371 



apparently an angulation on the margin. The shell appears to have 

 been umbilicatecl. 



TROCHOCERAS GEBHARDII HALL 

 (Plate 21, figures ?,a-b.) 



1852. Trochoceras gebhardii Hall. Paleontology of New York, volume 2, page 335, 

 plate 77, figure 2 ; plate 77 A figures la-d. 



This species, originally described from the Coralline limestone of 

 Schoharie county, is represented by several specimens from the Manlius 

 limestone of Erie county. A very perfect specimen (plate 21, figures 

 Sa-b) obtained by Vogt and Piper from the cement quarries, preserves 

 about 4i volutions, several being broken away at the apex. The shell 

 has the aspect of a large gastropod with rounded, strongly embracing 

 whorls. The umbilicus is wide and deep, the margin angular, cross-sec- 

 tion of body whorl irregularly subhemispherical. The apical angle of 

 the spire is 60 degrees, the sutures being moderately depressed below 

 the outline. No septa are shown. In a specimen from Williamsville, 

 referred to this species, the surface of the shell is marked with fine crowded 

 lines of growth. No other surface ornamentation is shown. 



Greatest diameter of the spire of the illustrated specimen, 75 millimeters. 

 This is about a volution younger than the t3 7 pe specimens, with which 

 it agrees in all the points which admit of comparison. Where the bod} 7 

 whorl has a height of 45 millimeters, the umbilicus has a diameter of 

 30 millimeters. 



In addition to the fine specimen obtained from Buffalo, a number of 

 compressed portions of whorls have been obtained from this rock at 

 Williamsville. These are in the state collection at Albany and appear 

 to represent older and larger individuals. The fact that septa are not 

 visible does not render the identification doubtful, as the form of the 

 shell is very characteristic. The greater portions of the type specimens 

 from Schoharie show no septa. 



LEPERDITIA SCALARIS JONES 

 (Plate 22, figures 6a-d.) 



1858. Leperditia gibbera var. scalaris Jones. Annals and Magazine of Natural His. 

 tory, third series, volume iv, page 250, plate x, figures 7a-b, lOa-b, 11. 



This species was described by Jones from specimens obtained from 

 the gray " Waterlime rock " of Williamsville by Sir Charles Lyell. One 

 of his specimens was half an inch in length by three-tenths of an inch 

 in height. The species is confined to the Manlius limestone in Erie 

 county, and occurs, besides at Williamsville, at Buffalo and Akron. It 



LIII— Bur.T,. Geot,. Soc. Am., Vot.. 11, 1899 



