SECONDARY AND TERTIARY FORMATIONS OF NORTH AMERICA. 155 



occasionally interpolated, always commencing by an abortive cellule. Surface of tbe 

 cellules presenting an imbricated appearance by tbe elevation of the distal end of each 

 above the proximal portion of the succeeding one. Cellules subquadrate, usually 

 rounded in advance, profound, opening large, subquadrate, oval or straight behind, 

 and rounded in advance, occupying nearly the whole surface. Margin raised 

 and convexly rounded or acute. Under surface of the colony nearly flat to deeply 

 concave, marked by lines towards the edge, indicating the rows of cellules, centre 

 smooth or papillate. 



Between the rows of cellules ai'e rows of vibracular cells, one vibracular opening to 

 every ordinary cellule. These openings are small, elongated and variable in form. 



Claiborne, Ala. Eocene. Common. 



CUPULARIA, Lam. 1821. 



Colony discoidal, fixed in the young state, afterwards free ; orbicular, convex above, 

 convex below; composed of cellules regularly placed in quincunx, without forming 

 lines and without abortive cellules. Cellules rounded or angular, broadly open, merely 

 separated by a common wall. Concave face marked by radiating, irregular lines and 

 pores. 



This genus bears the same relation to Discofliistrellarla as Slichopora does to 

 Lunulites. It can always be recognized by its discoidal form, cellules only on the 

 upper or convex surface, arranged in quincunx, without forming lines and without 

 abortive cellules. 



C. discoidea, G. and H. 



Orbitulites id., Lea, Contr. to Geology, p. 192, pi. 6, f. 205. 



Colony free, discoidal, attached in the young state usually to a grain of sand. Upper 

 surface convex, lower surface concave. Cellules subhexagonal, arranged on the upper 

 surface, in irregular quincunx, showing a tendency to form oblique radiating lines. 

 Opening elliptical, sometimes slightly irregular, placed in the centre of the cellule and 

 occupying about four-fifths of its surface. Borders between the cellules elevated into 

 sharp angular ridges which are common to all the cellules. From this ridge, the sur- 

 face slopes towards the mouth, which is surrounded by a very delicate rim, not always 

 present, however. 



Under surface marked by irregular radiating lines, with new ones occasionally 

 interposed and branching from the old one. Between these lines are numerous 

 large rounded pores piercing the lower wall and entering the cellules. These pores 

 are so placed that there are generally two rows in each space between the radiating 

 lines. 



From Claiborne, Ala. Eocene. 



40 



