296 [Oct. 1847. 



the disc, about thirteen in number ; anterior side with rugose, obtuse, oblique, 

 finer and more approximate lines. Length 2J. Rare. 



Lima staminea. 



Subovate, oblique, inflated, with fine radiating lines ; ears very small. 

 scarcely defined ; posterior margin rectilinear. Height 4-10. 



Very similar in outline to the Miocene species, L. papyria, but it is much 

 smaller, and has more numerous lines anteriorly. Rare. 



Pecten. 



A valve of a small species was obtained. It is orbicular and entire, and re- 

 sembles P. calvatus, (Morton.) 



Ostrea Vickshurgensis. 



Plicated; very irregular and adhering, the upper valve not flat, but swelling 

 in an irregular manner. Height 1|. 



There is nothing peculiar about this shell, yet it is clearly distinct from any 

 other species of the American Tertiary hitherto described. Common. 



Pholas triquetra. 



Subtriangular, depressed and angulated posterior to the middle, and with an 

 impressed line from beak to base ; surface with oblique lines anteriorly, and a 

 few radiating towards the margin ; posterior side reflected and with oblique lines 

 meeting the anterior ones at an angle ; a few obsolete radiating lines, one more 

 conspicuous than the others, near the margin. Length 6-10. Height . 



I found one valve only, which occurred on Dr. Smith's plantation. 



Madrepora M ississippiensis. 

 Rounded; cells numerous, very unequal in size, prominent, some of them 

 very large, the sides with strong longitudinal lines, and the interstices with 

 minute closely-arranged longitudinal lines; rays about fourteen, minutely 

 crenulated on the edge, alternated with a short plate ; centre with irregular 

 grains. Diameter 6-10. 



Madrepora Vickshurgensis. 



Irregular, ramose, somewhat flattened ; cells unequal in size, with a slightly 

 prominent margin; submargin depressed, striated : rays alternated with a short 

 plate ; centre granulated. 



A larger species than the preceding, the branches being sometimes an inch 

 in diameter. Abundant. 



Turbinolia caulifera. 

 Somewhat turbinate, rather long, with fine equal granulated longitudinal 

 lines; base stem-like; rays ramose ; larger end oval. Length 8-10. Rare. 



Lunulites. 

 Two or three species of Lunulites occur in the Eocene of Vicksburg. 



Lunulites Vickshurgensis. 

 Cup-shaped or somewhat conical, with very small cells, generally equal in 

 size, subaDgular, and between each series is a minute impressed radiating line : 

 interior striae ramose and very minutely crenulated. Height \. 



