321 Tertiary Foraminifera 27 



of the marginal keel is very variable though always more or less de- 

 veloped and serves to distinguish this species from Cristellaria 

 rotulata which it resembles; geologically it has a wide range, being 

 found as early as the Triassic (Lias; and still existing in present 

 oceans. 



Localsty. — Norfolk, Va. Well boring, depth 695 feet. 

 Crisfit^ld, Md. Well boring, depth 776 feet. 

 Cristellarii radiata. 



Syn. Robulina radia'.a Borneinann, Zeitsch. deutsch. geol. Gesell., vol. 

 vii, p. 334, pi. XV, fig. r, 1855. 

 Cristellaria radiata Bagg, Johns Hopkins Univ. Circulars, vol. xv, 

 p. 5, 1895- 

 Test nearly circular, moderately compressed, with circular, 

 raised umbilicus; final convolution showing ten strongly curv- 

 ed even chambers, marked externally by raised white septal lines 

 which become less distin<ft towards the peripheral margin; keel 

 quite definite and of the .same snow-white color as the rais- 

 ed septa, while the chambers are darker in color and are strong- 

 ly contrasted with the rest of the shell. The surface is smooth 

 :ind glistening; the aperture radiate; diameter 1.26 mm. 

 Horizon and locality . — Eocene; Woodstock, Va., rare. 

 Geological distributioji. — Tertiary. 

 Cristellaria rotulata. 



Syn. LenticuHtes j-otulata Lamarck, Ann. du Museum, vol. v, p. 18S, No . 

 3; Tableau Encyc. et Meth. pi. cccclxvi, fig. 5, 1804. 

 Cristellaria rotida'ta Parker & Jones, Phil. Trans., vol. civ, p. 345, pi. 

 xiii, fig. 19, 1865. 



Test involute, biconvex, smooth, peripheral margin sharp, non- 

 carinate, chambers numerous, eight or nine in the last con- 

 volution; septa moderately curved, visible externally as fine 

 lines; aperture elliptical, radiate. 



The genus Cristellaria although found so abundantly in the 

 New Jersey Cretaceous seems to be rather rare in the Atlan- 

 tic SlopeTertiary and is represented by only a few species. 

 Cristellaria wetherellii. 

 Syn. Marginulina zcetheretlii ]on^s, Morris's Cat. Brit. Foss., ed 2, p. 37, 

 1854. 

 Cristellaria wetherellii Brady, Chal. Rep't, vol. ix, p. 537, pi. cxiv, 

 fig. 14, 1884. 



Test elongate, compressed, pod-like, primordial segments more 

 or less involute, ultimate segments extended into a straight or 

 nearly straight series, surface of shell marked by large tubercles 

 more or less regularly arranged along the septal lines and also 

 upon the chambers of some segments. 



