138 



SHORTER CONTRIBUTIONS TO GENERAL (iEOLOCY, 1921. 



Genus GYPSINACarter, 1877. 



Gypsina rubra (D'Orbigny) Heron- Allen and Earland. 



PUitiorhulinii rubra ri'()rl>ii,'ii\-, .'VnniileK sci. nat., vol. 7, 

 p. 280, Xo. 4, 182(i. 

 Fornasini, Accad. sci. 1st. IJologna Mem., 6th ser., 

 vol. 5, p. 44, pi. 2, fig. 3, 1908. 

 Gypsina rubra (D'Drbigny) Heron-Allen and Earland, Zool- 

 Sof. London Trans., vol. 20, p. 725, pi. 53, figs. 35- 

 37, 1915. 

 Cushman, U. S. Geol. Survey Prof. Paper 129, p. 98, 

 pi. 22, fig. 3, 1922. 



This species, recorded from the Byram marl, 

 has also been found at tliree of the stations in 

 the Mint Spring marl, as follows: 



6462. Mint Spring Bayou, Vioksburg, Miss. 



6647. Chickasawhay River 1} miles southwest of Boice, 

 Miss. 



7671. "Brown's Cave," T-eaf River, Miss. 



This is a species from tlic Indo-Parific which 

 occurs in the lower Oliujocene of the Coastal 

 Plain of the United States. 



Genus PTTLVINTJLINA Parker and Jones, 1862. 



Pulvinulina byramensis Cushman. 



Pulvinulina byrameusi-s ('ushman, U. S. Geol. Survey 

 Prof. Paper 129, p. 99, pi. 22, figs. 4, 5, 1922. 



Test small, biconvex, rotaliform, consisting 

 of about three coils, seven to eight chambers 

 in the last-formed coil; on the dorsal side 

 sutures oblique and at a considerable angle 

 with the periphery, somewhat iind">ate; on the 

 ventral side the chambers extend in to the cen- 

 ter, wliich is usually not undiilicate; sutures 

 nearly straight; surface polishetl, punctations 

 appearing as light tubules against the trans- 

 lucent wall ; aperture near the inner end of the 

 chamber on the ventral side with a definite 

 valvular lip, the aperture hidden below but 

 when examined found to be composed, in the 

 adult, of several adjacent small rounded 

 openings. Diameter 1.5 millimeters or less. 



This species, which was described from 

 abundant specimens obtained in the Byram 

 marl at Byram, Miss., has occurred at all six 

 of the stations in the Mint Spring marl, as 

 follows ; 



6447, 6448. (Jlass Bayou, Vicksburg, Miss. 

 6451, 6452. Mint Spring Bayou, Vicksliurg, .Miss. 

 6647. Chickasawhay River IJ miles southwest of Boice: 

 Miss. 



7671. "Brown's Cave," Leaf River, Miss. 



At many of these stations it is common and 

 corresponds closely to the description given 

 above. 



Pulvinulina glabrata Cushman. 



PulrinuUim glabrata Cushman, U. S. Geol. Survey Prof. 

 Paper 129, p. 99, pi. 22 figs. 6, 7, 1922. 



Test biconvex, elongate, somewhat lobulate, 

 composed of about two coils, seven chambers 

 in the last-formed one, dorsal side convex; 

 sutures depressed, curved; chambers convex 

 between, rapidly increasing in size as added; 

 dorsal side very coarsely punctate, the sutures 

 somewhat limbate, ventral side umbilicate; 

 surface smooth and with very fine punctations; 

 sutures distinct; last-formed chamber with a 

 long, straight valvular lip across the whole of 

 the depressed umbilicus; aperture beneath the 

 lip. Length 0.5 millimeter. 



This species, which was rare in the marl at 

 Byi-am, Miss., has been found at four of the 

 stations in the Mint Spring marl, as follows: 



6448. Glass Bayou, Vickshurg, Miss. 



6451, 6452. Mint Spring Bayou, Vicksburg, Miss. 



7671. ■' Brown's Cave," Leaf River, .Mi.ss. 



It is in some ways related to the species 

 described and figured by Brady in the Clal- 

 hngtr report as Discorbhta ventricosa H. B. 

 Brady. It is more elongate than that form, 

 and the last-formed chamber especially gives 

 it an entirely different shape. It is one of the 

 most striking species in this lower Oligocene 

 material. 



Genus ROTALIA Lamarck, 1804. 



Rotalia byramensis Cushman. 



Rdtaliii hi/nimfimis Cushman, U. S. Geol. Survey Prof. 

 Paper 129. \k 99, pi. 2:!, fig. 1. 1922. 



Test unecjually biconvex, rotaliform, in the 

 last-formed coil six to seven chambers, dor- 

 sally with the chambers somewhat triangular; 

 sutures oblicjue, limbate, broad, of clear shell 

 material; ventral side with a large circular 

 mass in the umbilical region, with the sutures 

 deep and ending in a depressed ring about it; 

 aperture with a somewhat valvular lip, often 

 divided into several teeth; surface on the dor- 

 sal side somewhat roughened, on the ventral 

 side scrobiculate near the periphery, smoother 

 near the center. Diameter 2 millimeters or less. 



Specimens that may be referred to this 

 species were found at stations 6447 and 6448, 

 Glass Bayou, Vicksburg, Miss. 



The species is perhaps closest to Rotalia 

 armata D'Orbigny. The chambers are trian- 

 gular, and where there is a spinose projection 

 it is at the angle rather than at the middle 

 portion of the chamber, as in R. armata. 



