Maryland Geological Survey 491 



Sand. North and South Carolina. Eutaw Formation (Tombigbee Sand 

 member). Exogyra ponderosa zone, Mortoniceras subzone, Georgia. 

 Exogyra -ponderosa zone, Prentiss County, Mississippi. Ripley Forma- 

 tion. Exogyra costata zone, Georgia; Eufaula, Alabama; Union and 

 Tippah counties, Mississippi. Extreme top of zone, Pataula Creek, 

 Georgia. Selma Chalk. Exogyra costata zone, Wilcox County, Alabama. 

 Brownstown ( ?), Annona, Marlbrood, Nacatoch, and Arkadelphia Forma- 

 tions. Arkansas. Taylor and Navarro Formations. Texas. 



Tueritella tippana Conrad 



Turritella tippana Conrad, 1858, Jour. Acad. Nat. Sci., Phila., 2d ser., vol. 



iii, p. 333, pi. xxxv, fig. 19. 

 Turritella tippana Meek, 1864, Check List Inv. Fossils, N. A., Cret. and Jur., 



p. 19. 

 Turritella tippana Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, 



p. 700, pi. lxxix, figs. 6, 7. 



Description. — " Subulate ; sides straight ; volutions carinated with 

 revolving lines, two on each volution larger than the others, remote, one 

 nearly equal in size, nearly medial, and three other fine lines; whorls of 

 spire slightly carinated at base." — Conrad, 1858. 



Type Locality. — Owl Creek, Tippah County, Mississippi. 



" The dimensions of a large example, incomplete at the apex, are : 

 Height 69 mm., greatest diameter 22 mm., apical angle about 19°, num- 

 ber of volutions shown 10. Suture situated in the bottom of a broad, eon- 

 cave, revolving channel. Surface of the volutions between the margins 

 of the sutural channel nearly fiat or slightly convex; marked by four or 

 five strong, revolving eostas, the three lower ones being subequidistant, the 

 upper one more remote ; in the broader interspace between the uppermost 

 strong costa and the one next below is a much finer rib, and a similar one 

 about midway on the slope from the uppermost strong costa to the suture, 

 although this last one is sometimes strong enough, especially in the larger 

 shells, to be counted as one of the major ribs; in each of the interspaces 

 between the three lowermost strong costa? on the larger volutions there is 

 frequently a much smaller raised line ; and on the slope of the lowermost 



