SMALLER FORAMINIFERA FROM ILLINOIS 



353 



Family Rotaliidae Reuss 



Genus Eponides Montfort 



Eponides exigua limbata (Plummer) 



Plate 55, figures 11-13 



Pulvinulina exigua limbata Plummer, 1927, Texas 

 Univ. Bull. 2644, p. 152, pi. 11, figs. 4a-c; 

 Midway group, Paleocene, Texas. 



? Eponides sp. Cushman, 1940, Cushman Lab. 

 Foram. Research Contr., vol. 16, p. 71, pi. 12, 

 figs. 8a, b; Midway group, Paleocene, Ala- 

 bama. 



Test small, biconvex, peripheral margin 

 sharp or acute, indistinctly lobed, chambers 

 5 in final whorl, smooth; sutures very indis- 

 tinct, on dorsal side oblique, straight, nar- 

 row; ventral sutures flush, almost straight 

 but slightly curved from umbilicus; diam- 

 eter, 0.30 mm.; thickness, 0.20 mm. 



This species and its two varieties are 

 common in the Midway of Texas. The vari- 

 ety limbata is common in the basal strata 

 and var. exigua forms a good marker for the 

 lower beds. The Alabama form is limited 

 to the upper Midway. 



Genus Siphonina Reuss 



SiPHONiNA PRIMA Plummer 



Plate 55, figures 7-9 



Siphonina prima Plummer, 1927, Texas Univ. 

 Bull. 2644, p. 148, pi. 12, figs. 4a-c; Midway 

 group, Paleocene, Texas. — Cushman, 1927, 

 U. S. Nat. Mus. Proc, vol. 72, art. 20, p. 2, 

 pi. 2, figs. 4a-c. — Cushman, 1940, Cushman 

 Lab. Foram. Research Contr., vol. 16, p. 71, 

 pi. 12, fig. 10; Midway group, Paleocene, Ala- 

 bama; Navarro, Cretaceous, Gulf Coast Em- 

 bayment. 



Test circular, biconvex; peripheral angle 

 acute; margin lobate, chambers 5 in last 

 whorl; dorsal sutures curved, broad; ventral 

 sutures straight, narrow, excavated, radiate 

 from shallow central depressed area; diam- 

 eter, 0.35 mm.; thickness, 0.20 mm. 



It is common in the upper Midway of 

 Texas, Alabama, Arkansas, Mississippi, and 

 Tennessee, but is also present in the Upper 

 Cretaceous (Navarro) in these states. 



Family Globigerinidae Carpenter 



Genus Globigerina d'Orbigny 

 Globigerina compressa Plummer 

 Plate 54, figures 8, 9 



Globigerina compressa Plummer, 1927, Texas 

 Univ. Bull. 2644, p. 135, pi. 8, figs, lla-c; 

 Midway group, Paleocene, Texas. — Jennings, 

 1936, Bull. Am. Paleontology, vol. 23, p. 193. 



pi. 31, fig. 8; Hornerstown formation. Eocene, 

 New Jersey. — Toulmin, 1941, Jour. Paleon- 

 tology, vol. 15, p. 607, pi. 82, figs. 1, 2; Salt 

 Mountain limestone, Eocene, Alabama. 



Test small, quadrate, closely coiled, com- 

 pressed, margin lobate; chambers increasing 

 regularly, inflated, overlapping dorsally; 

 sutures strongly depressed; wall thin, 

 smooth, finely punctate; single aperature 

 arched; diameter, 0.30 to 0.40 mm. 



It is common in the upper Midway of 

 Texas. 



Globigerina triloculinoides Plummer 

 Plate 54, figures 12, 13 



Globigerina triloculinoides Plummer, 1927, Texas 

 Univ. Bull. 2644, p. 134, pi. 8, figs. lOa-c; 

 Midway group, Paleocene, Texas. — Jennings, 

 1936, Bull. Am. Paleontology, vol. 23, p. 193, 

 pi. 31, fig. 10; Hornerstown formation. Eocene, 

 New Jersey. — Glaessner, 1937, Moscow Univ. 

 Publ. Lab. Paleontology, vols. 2-3, p. 382, 

 pi. 4, figs. 33a, b; Lower Tertiary, Caucasus. — 

 Cushman, 1940, Cushman Lab. Foram. Re- 

 search Contr., vol. 16, p. 72, pi. 12, fig. 15; 

 Midway group, Paleocene, Alabama. — Toul- 

 min, 1941, Jour. Paleontology, vol. 15, p. 607, 

 pi. 82, fig. 3; Salt Mountain limestone. Eocene, 

 Alabama. 



Test very small, trochoid, periphery dis- 

 tinctly lobate; last volution formed by 3 

 large globular chambers which increase 

 rapidly in size; surface finely punctate; di- 

 ameter, 0.25 to 0.30 mm. 



It is common in the upper Midway of 

 Texas and Alabama and the Salt Mountain 

 limestone of the Alabama Wilcox. 



Family Anomalinidae Cushman 



Genus Anomalina d'Orbigny 



Anomalina acuta Plummer 



Plate 54, figures 3-5 



Anomalina ammonoides acuta Plummer, 1927, 

 Texas Univ. Bull. 2644, p. 149, pi. 10, figs. 

 2a-c; Midway group, Paleocene, Texas. 



Anomalina acuta, Glaessner, 1937, Moscow Publ. 

 Lab. Paleontology, vols. 2-3, p. 386, pi. 5, 

 figs. 39a-c. Lower Tertiary, Caucasus. — Toul- 

 min, 1941, Jour. Paleontology, vol. 15, p. 608, 

 pi. 82, figs. 9, 10; Salt Mountain limestone 

 (lower Wilcox). 



Test compressed, involute, about equally 

 biconvex, periphery acute; chambers nar- 

 row, numerous, 13 in last whorl; dorsal su- 

 tures distinct, limbate to slightly depressed; 

 ventral sutures thickened around umbilical 

 area, merging into prominently developed 



