MARYLAND GEOLOGICAL SURVEY 317 



aperture projecting downwards. Height of shell 1/15 of an inch." 

 Hall, 1845. 



Although this species has not been figured heretofore and its descrip- 

 tion was quite meager, there is no difficulty in distinguishing it from 

 other forms of Cyclora because of the angulation of the first whorl towards 

 the aperture. The other species of Cyclora, have rounded whorls and may 

 represent the young of such genera as Cyclonema or Hormotoma. The 

 angulated whorl of Cyclora parvula would suggest its relationship to 

 Lophospira or some similar genus. 



Common in association with Cyclora minuta Hall in the Mohawkian 

 and Cincinnatian rocks at Cincinnati, Ohio, and many other localities. 



Occurrence. MARTINSBURG SHALE .(Sinuites bed). Chambersburg, 

 Pennsylvania, and Strasburg, Virginia. 



Collections. Maryland Geological Survey, II. S. National Museum. 



CYCLORA HOFFMANNI Miller 

 Plate L, Fig. 27 



Cyclora hoffmanni Miller, 1874, Cincinnati Quart. Jour. Sci., vol. i, p. 313, 

 fig. 33. 



Description. Shell minute, the average length being about 1.50 mm., 

 consisting of an elongated spire made up of five or six volutions which 

 are round and increase gradually in size. Whorls quite convex, with a 

 deep suture; aperture nearly circular, directed slightly downward; sur- 

 face smooth. 



This neat, elongate little species is usually found associated with 

 Cyclora minuta and Micro ceras inornatum, and like them has little 

 stratigraphic value. In the Appalachians, however, these species are 

 known only in the Trenton portion of the Martinsburg shale. 



Occurrence. MARTINSBURG SHALE (Sinuites bed). Chambersburg, 

 Pennsylvania, and Strasburg, Virginia. 



Collections. Maryland Geological Survey, U. S. National Museum. 



