a»4 PALAEONTOLOGY OF NEW-YOBK. 



Ilolopca subcoiiica ( n. g.). 



Platb LIV. Fia. 1 a, b. 



Shell thin, subcouical : spire sharply elevated ; volutions five or more, 

 somewhat flattened above, the last one ventricose below and subanjru- 

 late on the periphery, equal in height to all the others ; aperture 

 round-ovate, entire, the outer lip acute at the margin and thickened 

 within : columellar lip thickened, with a slight umbilical groove or 

 depression upon the outside, not perforate." 



Surface marked by fine concentric striaj of growth. 

 The only difference between this shell and the modern Littorina is in the greater 



thickening of the columella, and the slight depression between it and the body of 



the shell. 



Fig. 1 a. View showing the aperture, which is represented with the peristome too much 

 thickened. 



Fig. 1 6. The anterior side of the same. 



Geological position and locality. In the tentaculite limestone near Auburn, Cayuga 



county. 



Holopea antiqua ( Yanuxem sp.). 



Plate LIV. Fig. 2 a, 6, & 3 a, 6. 

 Litiorina arUiqua : Vanuxbm, Geol. Report of the Third District of New-York, 1843, p. 112, f. 4. 



Shell subconic - ovoid ; spire elevated, obtuse ; volutions about four, 

 regularly rounded, the last one ventricose ; aperture rotund-ovoid : 

 columella slightly reflexed. 



Surface marked by fine striae corresponding to the lines of growth. 



This species occurs abundantly, in the form of casts, in the tentaculite limestone 

 of Schoharie and Herkimer counties. The specimen figured as cited is smaller than 

 the ordinary size of those which have fallen under my observation, and smaller than 

 most of the specimens which have been marked with that name by Mr. Vanuxem. 

 Fig. 2 a. A cast of this species of the ordinary size. 

 Fig. 2 6. A similar cast, which is a little more ventricose. 

 Fig. 3 a. A cast of a larger specimen. 



Fig. 3 6. The anterior view of a larger individual. The apparent extension of the shell on 

 the lower side is a misrepresentation of the artist. 



Geological position and locality. In the tentaculite limestone : Ilclderbcrg moun- 

 tains, Schoharie; Litchfield and Winfield, Herkimer county. 



