HELICINA OCCULTA 389 



iiig the largest recent specimens reported by Walker and Pilsbry 

 from Mount Mitchell, North Carolina. Below Dyersburg the 

 species is less common, and ranges from six to seven and one-half 

 millimeters in diameter. It should be noted that H. orbiculata, the 

 southern species, was not found in any of the Tennessee localities 

 here cited. 



In this connection it is desirable to correct another error which 

 was made in the same paper. On page 234 this statement appears : 

 "It is safe to say that all specimens of fossil Helicina reported from 

 south of Kentucky are H. orbiculata, fossils of that species being 

 known only from loess bluffs along the Mississippi to Kentucky. 

 Recent specimens of the species may be found from southern 

 Florida to Texas, and northward to Tennessee, and Jasper county. 

 Mo., the latter being the most northerly locality known." The 

 southernmost locality in which the writer has found fossil Helicina 

 occulta more recently is southwest of Covington, about forty miles 

 north of the south line of Tennessee. He has not found fossil H. 

 orbiculata north of Vicksburg, Mississippi, (about 200 miles south 

 of the Covington locality), though it is reported from Hickman, 

 Kentucky, as noted, and from Providence, Boone county, Missouri, 

 by Sampson, whb reports the variety tropica.'^ The latter locality is 

 near the center of the state of Miissouri, and is far removed from 

 known localities in which living or fossil forms appear. (Since this 

 paper was written the writer has visited the Providence locality and 

 found that this Helicina, with other terrestrial mollusk shells, is 

 found in a talus-like deposit along the bluffs on the north side of the 

 Missouri. These banks consist of a mingling of fragments of local 

 rock with a yellow loesslike material which covers the uplands to 

 the north, but which differs from loess in texture, and which is non- 

 fossiliferous on the uplands so far as the writer was able to ascer- 

 tain. It is clearly not loess, and the shells, evidently much more 

 modern than the upland deposit, are found only in the younger talus 

 near the base of the bluff's.) Sampson also reports typical living H. 

 orbiculata from Stone county, and the variety tropica from Jasper, 

 Barry, MacDonald, and Christian counties — all in Missouri. This 

 indicates an overlapping of the areas of distribution of the two 

 species, though so far as is known, they do not occur together, either 

 living or fossil. 



The vertical distribution of the fossils is also of great interest, 

 but this will be discussed in greater detail in a subsequent paper. 

 Sufffce it to say that the species is found in both of the common 



*P. A. Sampson, Trans, of the Academy of Science of St. TjouIs, vol. 

 XXII, p. 71, 1913. 



