MARYLAND GEOLOGICAL SURVEY 303 



Description. Shell conical, varying from 10 mm. to 40 mm. in width, 

 consisting of six or more volutions elevated into a spire and with an 

 umbilicus about one-half as wide as the entire diameter. Upper surface 

 of shell nearly flat with a faint groove near the edge; under surface 

 slightly angulate. Aperture irregularly rhomboidal. 



Under the name of Ophileta complanata a number of distinct species 

 of Canadian gastropods has been classed in the past half century and it 

 has only been by the study of specimens from the type localities in the 

 Mohawk Valley that the real characters of the species have been identified. 

 Vanuxem's very imperfect description is as follows : 



" [0. complanata] consists of many convolutions resembling a single 

 coil of cord formed on a flat surface, the diameter of the coil being usually 

 about an inch. From analogy of formation it evidently pertains to the 

 same genus with 0. levata. It is more rare than 0. levata, but is occa- 

 sionally met with in the same localities on the Mohawk." 



The type specimen of 0. complanata appears to be lost, but as noted 

 by Cleland, there is little doubt that the species described by him as 

 Pleurotomaria hunterensis has usually been identified as 0. complanata 

 in the Mohawk Valley. Both names undoubtedly refer to the same 

 species, especially since the occurrence of each is identical. Although 

 Vanuxem's description and figure are not sufficient for present-day pur- 

 poses, it seems best to recognize his name on account of the generic term 

 Ophileta. If the genotype 0. complanata should not be recognized' the 

 widely quoted genus Ophileta too would have to be dropped. The 

 synonymy is further complicated by the fact that Weller has based his 

 genus Poly gy rat a on a species from New Jersey apparently closely related 

 to Ophileta complanata. With regard to the numerous other references 

 to supposed 0. complanata, this is neither the time nor the place to discuss 

 them. Only a monographic faunal study of the entire Canadian can 

 clear up this complicated subject. 



Occurrence. BEEKMANTOWN LIMESTONE (Stonehenge member). 

 Vicinity of Hagerstown and Funkstown, Maryland. 



The type localities are in the Mohawk Valley of New York, Little Falls, 

 Canajoharie, Tribes Hill, Ft. Hunter, etc., where the species occurs in the 

 Tribes Hill division of the Canadian. 



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

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