130 EOCENE AND LOWER OLIGOCENE CORAL FAUNAS. 



sometimes only obscurely so. Margins not at all elevated. Calices elliptical ; 

 longer diameter about 3 mm., shorter 2.3 mm. Septa not exsert, usualh' 9 

 or 10, all of which reach the columella; there are usually about the same 

 number of smaller septa. They are moderately thick; thicker at the wall 

 and where they join the columella. Margins granular; cavity filling up 

 below. Columella short styliform, considerable calcareous thickening 

 around it. Dissepiments present, thin. 



Localities. — Sau Augustiue, Texas; Alum Bluff, Colorado River, Texas. 



Geologic occurrence. LoWCr ClaibornC. 



Types. — Wagner Free Institute of Science. 



I have referred this species to Madracis with considerable hesitancy, 

 because the collumella is so often nonstyliform, but it frequently is stj'li- 

 form. This species and Madracis ganei undoubtedly belong to same genus. 

 The distinguishing features between the two are: M. johnsoni has com- 

 pressed and larger branches, and larger calices, which are much more 

 crowded and are arranged more regularly. 



Madracis geegoeioi sp. nov. 

 PI. XIII, figs. 12 aud 12a. 



Colony small, branching. Corallites ci'owded together, A'ariable in shape, 

 joined directly by their walls, very little or no ctrnenchyma. Walls not 

 thick; upper surface rough. The immediate line of fusion of the walls of 

 neighboring corallites is indicated by a small distinct ridge. The margin 

 of each calice is marked by a small zigzag ridge. Between the ridg-e around 

 the margin of a calice and the ridge marking the line of fusion between the 

 walls of two corallites there is a slight groove. Calices shallow. - The 

 principal septa are ten in number; occasional rudiments of intermediate 

 ones are seen ; their faces granulate. At first they are weak, bixt become 

 secondarily thickened. Columella small, styliform, tliickening in old calices 

 by deposit around it. 



Diagonal diameter of calice 2.5 mm. (this is probably an average size); 

 wall about 1.6 mm. in thickness. 



Localities. — Hatclictigbee Bluff, Tuscahoma Landing, and Greggs Land- 

 ing, Alabama. 



Geologic occurrence. CllickaSaWaU StagC. 



