322 D. W. Zangdon, Jr. — Some Florida Miocene. 



Art. XLIV. 



-Some Florida Miocene; 

 Langdon, Jr. 



by Daniel W. 



Judge Lawrence Johnson, of the United States Geologi- 

 cal Survey, has pointed out the existence of Miocene deposits 

 occupying depressions in the Eocene White Limestone in the 

 vicinity of Tallahassee, Florida, but so far as the writer is in- 

 formed the formation has not as yet been noted as occurring 

 farther westward. 



In November, 1887, while making a section of the Cretaceous 

 and Tertiary rocks exposed along the course of the Chattahoo- 

 chee river, the writer had the good fortune to discover at Alum 

 Bluff some twenty-five miles below Chattahoochee or River 

 Junction, Florida, the following section : 



Alum Bluff, Ma. 



1. White sand, evidently marine but of recent formation, 30 feet. 



2. Black lignitic sand, very pyritous, and from the efflorescence 



of ferrous sulphate arises the name Alum Bluff. Varia- 

 ble in thickness, and unfossiliferous, . . 10-15 feet. 



3. Gray calcareous sand, highly fossiliferous, the principal shell 



being Mactra similis Con. Varies in thickness with pre- 

 ceding stratum, ...... 10-15 feet. 



4. Gray sand, slightly calcareous, no fossils, . . 5 feet. 



5. Light yellow sand, containing pockets of fossils. Where 



thei'e are no shells the sand is very calcareous. To water's 

 edge and probably slightly thicker than . . 35 feet. 



Owing to the high stage of water it was not possible to collect 

 many fossils from the lowest stratum, and only a partial series 

 from the upper fossiliferous stratum is given. 



Stratum 3 contains : 



Echora quadricostata Say 

 Buccihum porcinum Say. 

 Conus adversarius Con. 

 Oancellaria depressa T. & FT. 

 Typhis acuticostata Con. 

 Trochus pMlantrophus Con. 

 Fusus cinereus Say. 

 Dentalium attenuatum Say. 

 Oliva litterata Say. 

 Ranella (Eupleura) caudata Say. 

 Cadulus thallus Con. 

 ScalpeUum, nov. sp. 



Hipponix Bullii T. & H. 

 Crepidula plana Say. 

 Crepidula fomicata Say. 

 Trochita centralis ? 

 Grucibulum ramosum Con. 

 Pyrula pyriformis Con. 

 Drillia lunata Lea. 

 Naiica heros Say. 

 Natica duplicata Say. 

 Turritella, Purdenii ? T. & H. 

 Valuta sp. ? 



