A CONTRIBUTION TO THE INVERTEBRATE FAUNA OF 

 THE OLIGOCENE BEDS OF FLINT RIVER, GEORGIA. 



By William Healey Dall, 



Honorary Curator of Mollushs, United States National Museum. 



INTRODUCTION. 



The fossils described in this paper were collected on or near the 

 Flint River, Georgia, above and below the town of Bainbridge, by 

 Messrs. T. W. Vaughan, C. Wythe Cooke, and W. C. Mansfield, of the 

 United States Geological Survey. While their state of preservation 

 in many cases leaves much to be desired, the identification of the 

 fauna has some importance for the geology of that part of the coastal 

 plain of the southern United States. A feature of somewhat unusual 

 interest paleontologically is the presence in the upper bed of a rela- 

 tively large number of species of the Cerithiidae, several of them of 

 unusual size, recalling the analogous group in the Parisian Eocene 

 of France, and not paralleled in any of the other Tertiary horizons 

 of the United States so far as known. Attention was called to the 

 presence of these large Cerithia in our southern Tertiary by the writer 

 in 1890,^ but it was not until the present collection was made that 

 material suitable for study was obtained. 



These fossils are immediately separable into two groups charac- 

 terizing two zones, the upper zone being represented chiefly south of 

 Bainbridge, and the lower zone around and north of that town. The 

 extensive solution which these beds have undergone has probably 

 removed the upper bed in the vicinity of Bainbridge, leaving behind 

 more or less scattered remains of silicified fossils over or near the 

 present surface of the soil. 



Sixty-one species have been identified from the upper zone, of 

 which 29 are new to science. From the lower zone 39 species were 

 obtained, of which 9 are new. Five of the new species and 14 of 

 the others are common to both zones. 



Of the forms from the upper zone, omitting the new species, 51 per 

 cent are identical with species found in the Orthaulax pugnax zone at 

 Tampa, Florida, including the two species of Orthaulax. 



It is probable, allowing for the distance between the two locahties, 

 and for the shallower water indicated by the Flint River species, 



'Bull. Soc. Zool. France, vol. 15, 1890, pp. 97-98. 



PROCEEDINGS U. S. NATIONAL MUSEUM, VOL. 51-NO. 2162. 



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