Maryland Geological Survey 283 



Occurrence. — Eomnet Formatiox, Hamiltox Member. East bank 

 Evitts Creek below Wolfe Mill; on Ilaneoek-Harrisonville Road about 2 

 miles north of Hancock; B. & 0. E. E. cut at Hancock Station, 

 W. Va. (?). 



Collections. — Maryland Geological Survey; jSTew York State Museum; 

 American Museum of Natural History. 



Subgenus TREPOSPIRA Ulrich and Scofield 



Pleorotomaria (Trepospira) rotalia Hall ( ?) 

 Plate XXXV, Figs, 9, 10 



Pleurotomaria rotalia Hall, 1861, Descriptions of New Species of Fossils, 



p. 18. 

 Pleurotomaria rotalia Hall, 1862, Fifteenth Rep. N. Y. State Cab. Nat. Hist., 



p. 46, pi. V, fig. 11. 

 Pleurotomaria rotalia Hall, 1879, Pal. N. Y., vol. v, pt. ii, p. 71, pi. xix, figs. 



20-25. 

 Trepospira rotalia Ulrich and Scofleld, 1897, Geol. Minn., vol. iii, pt. ii, 



p. 957. 

 Trepospira rotalia Grabau and Shimer, 1909, N. Am. Index Fossils, vol. i, p. 



648. 



Description. — ''Shell small, depressed-trochiform ; apex minute; spire 

 consisting of about four volutions, which gi'adually expand to the aper- 

 ture; slope of the spire from the apex to the periphery nearly in the 

 same plane, being very slightly convex; aperture subquadrate; lower side 

 concave, with a comparatively large umbilical depression, which is sur- 

 rounded by a distinct areola. Surface very finely and closely striate 

 parallel to lines of growth ; striae not prominent, sometimes obscurely 

 fasciculate, and always bending abruptly backward as they approach the 

 narrow peripheral band ; suture line depressed and narrowly canaliculate, 

 with sometimes a subdued or obsolescent revolving carina just below, 

 near the upper margin of the volution." Hall 1879. 



The specimens are mainly broken, smooth, internal impressions not 

 showing much more than the body-whorl and a part of the first volution 

 of the spire, however, so far as preserved they apparently agree with 

 figure 25 of the Palaeontology of New York which represents an enlarged 



