246 



A. F. Foerste — Chipola Miocene of 



water current seems to have split near the northeastern part of 

 present Florida, and while a part flowed along the eastern and 

 southern margins of the then greatly extended Ocala islands, 

 another part passed by way of the Okefenokee passage to the 

 westward and permitted a cold water fauna to extend all along 

 the southern border of the Miocene continent, almost coinci- 

 dent with present northern Florida, so that the two faunas 

 Chipola and Chesapeake, though probably to a considerable 

 extent contemporaneous, in point of time, are stratigraphically 

 very distinct here and represent different geological ages for 

 this southern area. How completely changed the forms of 

 life became by this deflection of currents, can only be appre- 

 ciated by one who has had the good fortune to collect along the 

 Appalachicola and Chipola rivers. 



Fossiliferous exposures of Chipola age north of the well 

 known localities at Alum Bluff and south of Bailey's Ferry are 

 known only at one place, half way between Bainbridge and 

 Fowltown in Georgia and thence eastward for some distance. 

 These localities discovered by Professor Raphael Pumpelly * 

 are about 40 miles northeast of the Alum Bluff exposures, and 

 represent a northing of about 22 miles across the strike. Their 

 chief interest lies in the fact that they represent the extreme 

 northern limit to which the Chipola current was able to pene- 

 trate ; they are in fact immediate off-shore deposits. This is 

 shown not only by the very comminuted and strongly washed 

 and rounded shell fragments which characterize these hori- 

 zons, often making their determination very difficult, but also 

 by the presence of pulmonate land shells : an undoubted Helix 

 and an apparent Bulimulus as indicated in the list given later. 



Another point of interest consists in the fact that these fos- 

 sil localities have recently been shown by the still unpublished 

 work of Prof. Pumpelly to constitute a definite horizon in the 

 red clay hills of the region, overlying the Chattahoochee for- 

 mation which constitutes the lower portion of these hills. 

 ISTow these red clay hills form a part of a great series becom- 

 ing a sort of plateau in southwest Georgia and adjacent 

 Florida, and having those lithological characteristics which 

 would lead them to be classified as Lafayette clays, where the 

 determination of the Lafayette is not the result of detailed 

 work over areas not too large to prevent definite correlation. 

 It is becoming evident in consequence of Prof. Pumpelly's 

 stratigraphical studies that the red clay hills of this country 

 characteristically present Chattahoochee at the base, Chipola 

 higher up, still higher horizons representing undoubtedly the 

 Alum Bluff sands, and whether any higher horizons are present 

 remains to be determined. 



W. H. Dall, Correllation papers, Neocene ; under Georgia. 



