874 



SCIENCE. 



[N. S. Vol XII. No. 310. 



permission from the Director of the Geolog- 

 ical Survey to visit the locality during the 

 present field season. 



Three localities where fossil reef corals'of 

 the same horizon are found were studied- 

 The best and most important one is on the 

 left bank of the Flint River, about a quar- 

 ter of a mile below where Russell Spring 

 empties into the river. About a half mile 

 farther down stream on the right bank is 

 another exposure. At Cherry Chute, some 

 three miles below Bainbridge and about a 

 mile above Russell Spring, is another ex- 

 posure of the same rock on the right bank 

 of the river. The following section was 

 observed at the locality just below Russell 

 Spring and the locality one-half mile far- 

 ther down stream. It should be stated that 

 the Vicksburgian Oligocene was not seen 

 at the latter locality. 



1. Yellow clay and yellow argillaceous 

 limestone, composed largely of comminuted 

 shells, spines of sea-urchins. Fossils fairly 

 numerous, but only a few species are repre- 

 sented ; they are a large species of Orbitoides, 

 several species of echinoids, Echinocyamus 

 is one of the genera, and Pecten (Pseudamu- 

 sium) ocalensis Dall. The stratum belongs 

 to the Vicksburgian Oligocene. Its upper 

 surface is very irregular, showing decided 

 evidence in favor of Professor Pumpelly's 

 conclusion that the Vicksburg is separated 

 by an erosion unconformity from the suc- 

 ceeding Chattahoochee. Thickness (to wa- 

 ter's edge) a few feet. 



2. Bluish or whitish sandy clay, some- 

 times purplish, rarely greenish. In this bed 

 large limonitic segregations are abundant. 

 The segregations occur in pockets often of 

 many feet in horizontal extent and several 

 feet thick. The purplish clay in places 

 contains carbonaceous particles. Thick- 

 ness variable, from 5 to 10 feet or even more. 



3. Cherty limestone, or chert — the fossil 

 coral reef. In the section this does not ap- 

 pear as a connected stratum, but in large de- 



tached masses, which very often have rolled 

 down the incline to the river, but some are 

 in situ. Dr. Dall identified from this bed 

 for Professor Pumpelly Orthaulax and Amau- 

 ropsis burnsi, referring it to the Chatta- 

 hoochee horizon.* Molluscan remains are 

 abundant, but the state of preservation is 

 poor. The shells are completely silicified, 

 or there are only surface casts or chalce- 

 donic internal fillings. Pecten, Venus, Xeno- 

 phora and Natica are common genera. A 

 very large portion of the rock is composed 

 of coral heads, some more than a foot in 

 diameter. The specimens of corals are more 

 easily removed from the matrix in which 

 they lie than are the moUusks. Thickness, 

 3 feet. 



At Cherry Chute the thickness certainly 

 exceeded 8 feet. 



4. Reddish sands, containing some gravel* 

 8 feet. 



The bed of the greatest interest is No. 2, 

 The corals from it belong to the basal por- 

 tion of the Chattahoochee and not, as I once 

 supposed, to the Vicksburg. 



The following is a rough characterization 

 of the coi'als found in the stratum : 



Caryophylliidse (probably Paracythus) 1 sp. 



Other simple corala (several species) 2 or more. 



Bifurcating forms 2 



Calamophyllia 1 



Ocnlinidse 1 



Stylophora, probably 3 



Astrocoenia, probably 2 



Orbicella, at least 3 



Siderastrea 1 



Mesomorpha ? 1 



Isoporidse ( Madreporidae Auct ), at 



least 2 



Poritidse, about 3 



Alveopora 1 or more 



and several others. 



My estimate is that there are between 

 twenty-five and thirty species. 



This is the richest fossil coral fauna 



* Dall and Stanley-Brown, Bull. Qeol. Soc. Amer., 

 Vol. v., 1894. Pp. 151, 152. 



