MAltVl.AMJ GEOLOGICAL SUUVEY 2b7 



Genus NONIONINA d'Oibigny. 

 KOMOMXA AFFINIS Kc'USS, 



V\n\v, LXIV, Fig. 9. 



Xonioiiiiiii iijfinis Heiiss, 1 s.") 1 , Sit/.miiisb. d. k. Akiid. Wiss. Wieii, vol. iii, p. 72, 



pL V, tig. 82. 

 N'onioniiia (ifflnix Bajfji^, IHiKJ, Hull. 141, U. S. GeoL Survey, p. 92. 

 .Yonioninn (iffltils Bags,', 18(tS, Hull. Aiuer. Pal., No. 10, p. 30, i)l. i, tig. 5. 



Descriplioii. — Test small, orbicular, strongly compressed, umbilicate, 

 finely perforate; chambers ten to twelve, small, flat, slightly curved, sep- 

 arated by fairly distinct band-like septal lines; septal plane of ultimate 

 chamber somewhat higher than broad and quite large; aperture short, 

 semilunar. Diameter, 0.32 mm. Professor Eeuss' figure agrees fairly 

 well with our specimens but there are twelve chambers visible in the 

 last volution. According to Eeuss this species is closely related to 

 Nonionina punctata d'Orbigny, but the latter is thicker in transverse 

 section. 



Occurrence. — Xaxjemoy Formation. Woodstock. 



Collection. — Johns Hopkins University. 



• " Genus AMPHISTEGINA d'Orbigny. 



Amphistegina lessonii d'Orbigny. 

 Plate LXIV, Fig. 10. 



AinpMstegina lessonii d'Orbigny, 1826, (parte) Aun. Sci. Nat., vol. vii, p. 304, No. 3, 



pi. xvii, figs. 1-4. 

 Amphistegina lessonii Brady, 1884, Chal. Rept., vol. ix, p. 740, pi. cxii, flgs. 1-7. 

 Amphistegina lessonii Bagg, 1896, Bull. 141, U. S. Geol. Survey, p. 92. 

 Amphistegina lessonii Bagg, 1898, Bull. Amer. Pal., No. 10, p. 42, ]3l. i, fig. 6. 



Description. — Test circular, compressed, transverse elliptical; superior 

 only slightly more elevated than the inferior; superior surface shows 

 about eighteen angular segments; inferior surface less distinctly cham- 

 bered, more irregular; chambers narrow, angular, visible in transmitted 

 light; surface smooth and of a brownish-yellow color. Diameter, 1.47-3 

 mm. 



Professor Brady states that this species shows great variation in the 



amount of convexity. Our specimens agree more closely Avith his Fig. 4 

 17 



