252 A, F Foerste — Chipola Miocene of 



While there have been already some very valuable results at- 

 tained in the study of the paleontological remains of certain local- 

 ities in the Gulf Miocene, chiefly due to the energy of Mr. W. H. 

 Dall, the examination of the geology can hardly be said to have 

 more than begun ; and the present paper is offered only as 

 one among pioneers in this direction. A list of the fossils of 

 the Gasteropod Gully locality and of the exposures of the 

 same horizon within a radius of two miles towards the east 

 and southeast are here appended. Owing to the lack of oppor- 

 tunity for the present to complete their study by a comparison 

 with the original types scattered in various museums, the publica- 

 tions used in their identification are indicated in the last column, 

 and the appended remarks will sufficiently describe the particular 

 forms discovered. The main value of this list however, con- 

 sists in the comparison of the Gasteropod Gully specimens as 

 types, with the corresponding or nearly related species found 

 elsewhere in the Appalachicola embayment, and actually in the 

 writer's possession, a denotes a moderate variation from the 

 forms typical of the Gasteropod Gaily Chipola ; b denotes dis- 

 tinct variations, therefrom, and c suggests only a similar general 

 habitus and form. 



Notes on the preceding species. 



1. The Chattahoochee, Alum Bluff and Bailey's Ferry speci- 

 mens are decidedly of the Ostrea divaricata type, but from 

 Gasterpod Gully only the free valve is known. 2. The three 

 striae along the back of the ribs are not so strong as is indicated 

 in Conrad's figure; the Chattahoochee specimens reach only four- 

 sevenths of the normal size and have 16 or 17 ribs. 3. Posterior 

 ribs strongest; umbonial ridge very strongly defined posteriorly 

 near the beak ; a depressed area or groove anterior to the same 

 near the margin, anteriorly to which with a concavely sinuous 

 outline the breadth of the valves is diminished. 4. Anterior half 

 strongly depressed ; ribs (19 or 20) and interspaces about equal ; 

 cross striations strong and tuberculate over the anterior ribs, 

 squamose towards the umbonial slope, and coarsely striate pos- 

 teriorly ; a narrow plication follows the posterior hinge line, suc- 

 ceeded below by a broad plication, then two narrow ones, then a 

 broad one, after which the broader plications of the umbonial 

 slope come in. 5. Not exceeding 45 mm in length ; with elevated 

 concentric ridges about 2 mm apart, or less regularly arranged. 

 6. The Chattahoochee specimens are typical, the Gasteropod Gully 

 one is relatively broader, and those from Alum Bluff are 

 smaller. 7. In Chattahoochee specimens 4 to 5 revolving 

 striae ornament the whorls of the spiral. 8. Nucleus un- 

 known; remainder 2l , 5 mm long, with 7 whorls, the earlier ones 

 more rapidly tapering, the last 7-7 mm in diameter, with 9 ribs. 

 9. Form of the spire and of the posterior end of the aperture 

 between M. ballista, Dall and M. bella, Conrad ; outline of the 



