GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 



443 



and at White Springs, Florida, T. W. Vaughan and L. W. Ste})hen- 

 son, collectors. Station 7076, in the Chattahoochee formation, 12 

 miles below Bainbridge, Georgia, on the east bank of Fhnt River, 

 collected by C. W. Cooke and W. C. Mansfield. 



Type.—]S[o. 325183, U.S.N.M. 



Paratype. —No. 325155, U.S.N.M., the specimen described below. 



The diagnosis of S. hillsboroensis was written and the figures made 

 to illustrate it before an intei-csting specimen from 12 miles ])elow 

 Bainbridge came to my notice. This specimen, which is a subcy- 

 cihndrical segment of a more or less columnar corallum, has a maxi- 

 mum horizontal diameter of 160 mm., and a vertical thickness of 75 

 mm. The entire corallum was rather large. The septal margins 

 over considerable areas are somewhat elevated around the calicular 

 fossae and the rims are separated by depressed interspaces that in 

 places are as much as 2 mm. across. Adjacent corallites, however, 

 are separated by simple common-walls. The number of septa in 

 fully developed calices ranges from a few less than to about four 

 complete cycles, grouped as in the types of the species. The septal 

 dentations are strikingly large. The following table gives the dimen- 

 sions of several corallites, the number of septa, the number of septal 

 teeth within 1 mm., and the character of the columella: 



Dimensions of corallites, etc., in Siderastrea hillsboroensis. 



Corallite No. 



Diameter corallites. 



5 by 7.5 mm.. 

 4.5 by 6.6 mm. 

 5.5 by 6 mm. . , 

 6 by 6.75mm.. 

 5.25 by 7 mm . . 

 4.5 by 6.5 mm.. 



Number 

 of septa. 



Septal teeth. 



Columella. 



4 in 1 mm. . . 

 do 



5 in 1.5 mm. 



6 in 1.5 mm. 

 do 



Weak. 

 Do. 

 Do. 



S. Mllshoroensis has some corallites of nearly the same size as those of 

 S. silecensis, but the}^ average smaller; it has thicker and relatively 

 fewer septa, which fuse into groups farther from the columella; and 

 the septal teeth are distinctly coarser. 



8. SIDERASTREA SIDEREA (Ellis and Solander). 



Plate 114, figs. 2, 3; plate 122, figs. 1, 2, 2a, 2b, 3, 3a. 



1786. Madrepora siderea Ellis and Solander, Nat. Hist. Zooph., p. 168, pi. 49, 



fig. 2. 

 1816. Astrea siderea Lamarck, Hist. nat. Anim. s. Vert., vol. 2, p. 267. 

 1830. Astrea (Siderastrea) siderea De Blainville, Diet. Sci. nat., vol. 60, p. 335. 

 1834. Astraea tricophylla Ehrenberg, Cor. Eoth. Meer., p. 95 (of separate) 



(Jide Miine Edwards and Haime). 



