OF NEW TERTIARY FOSSILS. 127 



PHOLAS. 



P. TRiQUETRA. PI. 13, fig. 3. — 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. 



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



MADREPORA. 



M. MIS3ISSIPPIENSIS. PI. 13, fig. 22. — 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. 



M. vicKSBURGENsis. — 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. 



T. CAULiFERA. PI. 13, figs. 33, 34. — Somewhat turbinate, rather long, with fine equal granulated 

 longitudinal lines ; base stem-like ; rays ramose ; larger end oval. Length 8-1 0. Rare. 



LUNULITES. 



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



L. VICKSBURGENSIS. — Cap-shaped, or somewhat conical, with very small cells, generally equal in size, 

 subangular, and between each series is a minute impressed radiating line ; interior striae ramose and 

 very minutely crenulated. Height J. 



All the foregoing species of organic remains are now included in the collection of 

 the Academy. 



33 



