Maryland Geological Survey 671 



cate carina' near u])pei- suture and about five revolving carinate bands on 

 lower side of volution. Faint concentric strine cross upper volutions 

 obliquely, becoming obsolete on most of body volutions. 



Lengtb 35 mm.; diameter 20 mm. 



This shell differs slightly from the typical form, occurring in the 

 Chemung of New York, in the less ventricose character of the body volu- 

 tion and in the position of the upper carina? which are nearer the upper 

 suture instead of being in the center of the volution as in that form. 



Occurrence. — Jennings Formation, Chemung Member. Town 

 Creek, 2228. Parkhead Member. Williams Eoad, on Polish Mountain, 

 1660; 2 miles west of Pawpaw, 1493; 2i/o miles above mouth of Sideling 

 Hill Creek. 



Collection. — Maryland Geological Survey. 



Genus CYCLONEMINA Perner 



Cyclonemina crenulistriata n. sp. 



PlateLXVIII, Figs. 1-4 



Dcscripiioii. — Shell conical, volutions increasing gradually in diameter 

 to body volution, which is ventricose; height of shell greater than the 

 diameter of last volution. Absolutions four or more, high, flattened on 

 periphery. Umbilicus small, covered by the thickened and reflected lip. 

 Surface bearing strong, distant carinse, of which 3 to 4 are on upper 

 volutions, 14 to 18 on body volution. Carinaa vary in width, narrower 

 one often arising in interspace between the broader. The wider carina 

 are nearly flat. Transverse strige cross carina? but do not appear in inter- 

 space. Substance of shell very thick. 



Length of larger individuals 35 mm.; diameter 30 mm. Other speci- 

 mens are somewhat narrower proportionately. 



The genus Pohjtropus is defined by Perner ^ as having simply curved 

 not sigmoidal, transverse stris", and usually possessing a well-developed 

 mnbilicus, while the genus Ci/cloncmina lias sigmoidal transverse striae 



^ Syst. SiL Bolieme, vol. iv, th. ii, p. 20.5. 



