H8 DALL AND STANLEY-BROWX — APALACHICOLA RIVER GEOLOGY. 



Introduction. 



The most complete series of Neozoic rocks in continuous succession 

 which has yet been observed on the Gulf coast is that which is exhibited 

 in the natural sections exposed in the bluffs of the Flint and Apalachi- 

 cola rivers, in southwestern Georgia and western Florida. For this 

 reason the series has been adopted in various publications * as a standard 

 by which to correlate the different Neocene beds of this general region. 

 The longest continuous series of beds in one section is exposed at Alum 

 bluff, in township 8, range 1 north, section 24, Liberty county, Florida. 

 Attention was first called to this series by Mr D. W. Langdon in 1889 ,t 

 from observations made two years earlier. At the suggestion of Mr T. H. 

 Aldrich, who had identified Langclon's fossils, and, in cooperation with 

 him, Mr Frank Burns, of the United States Geological Survey, was sent 

 to Alum bluff in 1890, and a collection and section made by him were 

 sent in. This section, in which the heights were determined with a 

 pocket aneroid by Mr L. C. Johnson, who visited the bluff w^hen Mr 

 Barns was at work, was printed on page 113 of Bulletin 84, already 

 referred to. In December, 1891, under the instructions of Mr George H. 

 Eldridge, Alum bluff was visited by a party, including Messrs L. C. 

 Johnson and Edmund Jussen, from whom separate reports and sections 

 are on file in the archives of the United States Geological Survey. 

 Subsequently Dr J. W. Spencer with a party, and Professor Raphael 

 Pumpelly, assisted by Mr A. F. Foerste, examined this locality. A val- 

 uable paper by the latter gentleman has recently appeared;|; and Professor 

 Pumpelly has published§ additional data establishing an unconformity 

 at the base of the Neocene in this series. 



In the above enumeration only those visitors through whom informa- 

 tion about Alum bluff has reached the writers of this paper are referred 

 to, though several other observers are believed to have visited tiie locality. 



The importance of the Apalachicola section for southern geology is 

 manifest, and the fact that there were serious discrepancies between the 

 various accounts of it hitherto accessible, not only concerning the suc- 

 cession of the beds and their exact nature, but even in reaiard to so 

 simple a matter as the height of the bluff, decided the writers of this 

 paper, with the approval of the Director of the United States Geological 

 Survey, to reexamine the subject on the spot. Previous observations 



* Bulletin 84 (Neocene), U. S. Geological Survej'', 1891. Transactions Wagner Free Inst. Sci. 

 vol. 3, 1890-'92, etc. 

 t Am. Jour. Sci., third series, vol. 38, p. 324. 



I Studies on the Chipola Miocene, Am. Jour. Sci., vol. 40, October, 1893, pp. 244-54. 

 I .\m. Jour. Sci., vol. 46, December, 1893, pp. 445-447. 



