•±4 Foerste — Eocene and Miocene of Georgia and Florida. 



free from the surrounding rock."- This bed is the best collect- 

 ing ground for Yicksburg fossils so far found in southwest 

 Georgia ; the variety and state of preservation of the fossils is 

 excellent, and the bed has also decided value for purposes of 

 correlation since nothing similar has so far been found else- 

 where in the Yicksburg in southwest Georgia. It is with this 

 laver that the bed dug up in the ditch near the Natural bridge 

 on the Chipola River north of Marianna in Florida, is corre- 

 lated. Immediately above the Bainbridge marl occur one 

 or two silicified layers, represented at the Natural Bridge north 

 of Marianna by the more massive silicified layer forming the 

 top and the walls of the natural cave, a short distance east of 

 the bridge, locality 5. 



(c) The next silicified layer occurs at localities 1 and 2. The 

 first presents many sponges, Orbitoides, simple corals, Hin- 

 nites, Pectunculus, including also a small, radiately strongly 

 ribbed species of this genus, Cytherea, Cerithium Mariannensis, 

 Melongena, and Mitra. At the second, Pectunculus, Pecten 

 and Cytherea were found. It is possible that this layer is also 

 represented by the massive silicified limestone at the cave near 

 the Natural Bridge north of Marianna. At 2J silicified rock 

 occurs, containing many sponges, some massive corals, Pecten, 

 and Cassidaria (Sconsia). "Whether this forms a distinct layer 

 or not, is undetermined. 



(d) The next silicified layer is represented by localities, 3 

 and 4. The first of these is near Russell Springs, a picturesque 

 limesink, surrounded by steep banks, filled with water, in which 

 cypress trees grow abundantly. Numerous fossils were found 

 here, the species being usually the same as those seen along 

 the river at Bainbridge, either in the marl or in the silicified 

 layers immediately above. At 4 there were many sponges, 

 simple corals, Pecten, Hinnites, Pectunculus and Ampullina. 

 This bed is probably represented at Marianna by the silicified 

 beds above the level of water at the bridge across the Chipola 

 River east of the town, locality 2. 



(e) The next silicified layer is exhibited at localities 5 and 6. 

 At 5, numerous small bowlders are carted together at the top 

 of the bank ; they contain Orbitoides. Lunulites, a Pecten 

 with 7 or 8 broad ribs, numerous specimens of Turritella, the 

 precursor of T. variabilis Conrad. This species occurs in the 

 Yicksburg, Chattahoochee, Chipola, and Chesapeake of S.W. 

 Georgia, aud western Florida. It may be characterized as hav- 

 ing a spiral lib a little posterior to the anterior suture, another 

 rib a little posterior to the median line, a deep groove or con- 



* Loc. cit., p. 445. with Echinoeyamus parvus, Scutella Lyelli, Pecten Poul- 

 soni. and unknown species of Amusium, Pectunculus, and Cerithium as frequent 

 fossils. 



