TO GEOLOGY. 113 



A. elevatus. Plate 4. Fig. 98. 



Description. Shell subulate, polished, furnished with a 

 single transverse furrow near the middle of the whorl ; sub- 

 stance of the shell rather thick ; spire very much elevated ; 

 suture furrowed ; columella with one large and one small 

 fold ; whorls flattened above the medial furrow ; mouth ob- 

 lique, subovate ; outer lip simple. 

 Length .... Breadth .2, of an inch. 



Observations. This interesting species differs from any 

 with which I am acquainted. The specimens I have been 

 able to examine (three) are all more or less broken. The 

 best one which is here figured is broken at the top, six 

 whorls only remaining. It most probably had about ten. 

 At first view of the mouth, the large fold only would be ob- 

 served. More internally, and below it, a very minute one 

 may be seen with the aid of the miscroscope. In one speci- 

 men this lower fold appears to be disposed to separate into 

 two other individuals may show this character more 

 developed. 



A. melanellus. Plate 4. Fig. 99. 



Description. Shell subulate, smooth ; substance of the 

 shell rather thick ; spire elevated, pointed ; suture sharply 

 impressed ; columella with a single large fold ; whorls six, 

 flattened ; mouth ovate, outer lip simple. 



Length 7-20ths, Breadth 3-20ths, of an inch. 



P 



