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\s< Murchisonia attenuata. — Shell subulate, elongate ; spire 

 tery gradually tapering ; volutions nine or more, flattened, 

 scarcely convex in the middle, and marked by a spiral band 

 which is margined on either side by a strong elevated line ; 

 suture bounded on each side by a sharp elevated line which 

 is smaller than those bordering the spiral band ; aperture 

 tranverse ; umbilicus none. 

 Locality. — Spergen Hill, la. 



I Murchisonia vermicula. — Shell cylindrical, abruptly ta- 

 pering at the apex ; volutions from six to ten, moderately 

 convex in the middle, and scarcely diminishing for the first 

 four or five turns above the base, but becoming more 

 abruptly contracted above ; surface of each volution ♦ 

 marked by two very prominent revolving striae, having a 

 space between them on the periphery, and a single finer line 

 below and one above near the suture ; the last volution not 

 ventricose, and marked by a fifth revolving striatiom which 

 is a continuation of the suture line ; aperture broadly oval, 

 rounded below ; columella imperforate. Shell minute. 

 Length *14 of an inch. 



Locality. — Spergen Hill and Bloomington, la. 



^/Murchisonia turritella. — Shell subulate, elongate, grad- 

 ually tapering to the apex ; suture distinct ; volutions about 

 nine ; equally rounded, the last one slightly ventricose ; 

 surface marked by closely arranged, rounded, revolving 

 striae, which are stronger on the middle of the volution ; 

 five revolving striae on each volution of the spire, and 

 about seven on the last volution ; aperture sub-ovate ; col- 

 umella slightly extended, and curved around the aperture, 

 imperforate. 



Length *18 to *50 of an inch. 



Locality. — Spergen Hill. 



1/ Murchisonia elegantula. — Shell elongate-conical ; spire 

 composed of about six or seven volutions which are obliquely 

 flattened on the upper side ; and angular near the base j suture 



