68 Bulletin 15 378 



group for the formation. Hilgard,* during the same year, 

 adopted Conrad's correlation. 



In 1895, Dr. Dallf placed the Shell Bluff group among the 

 transitional beds overlying the Vicksburgian stage. During the 

 same year, however, typical Eocene fossils were colledled by Prof. 

 Harris from the Ostrea bed. Several years later, Mr. Vaughan 

 published a note to the effedl that he had also obtained Eocene 

 shells from this locality. The position of the Shell Bluff group 

 in the Eocene was thus unquestionably established. 



Vicksburg limestone. Vicksburg or Orbitoibes limestone, 

 merging at the base into Jackson, from which it is with difficulty 

 separable, extends as country rock over a much wider area in 

 Georgia than Dr. Spencer^ has assigned to it. As indicated on 

 the map, it forms a broad belt running northeast and southwest 

 across the state. 



Remnayit of Vicksburg limestone at Rich Hill. An interesting 

 trace of its former northward extension was found by Prof. Harris, 

 at Rich Hill, about 12 miles north of Fort Valley, and six miles 

 east of Roberta. This remnant shows a regular mauvaise-terre 

 strucfture. The beds containing fossils are on a hillside. 

 The uppermost layers are reddish sands. These are followed 

 by Vicksburg limestone with Pe£len, Scutella and Bryozoa in 

 abundance. Below are whitish, or bluish white, sands and clays. 

 No sedlions were made, but it is estimated that about 100 feet of 

 sands are exposed. This isolated remnant has, for some reason, 

 resisted the erosion that has removed the rest of the limestone 

 from the valley between Perry and Knoxville. 



Time-interval between Vicksburg and Chattahoochee series. At 

 Baindridge, Blue Springs and Wiley's Eanding, on the Flint 

 River, the Vicksburg is overlaid by beds of the Chattahoochee 

 series. Prof. Pumpelly|| has noted near Bainbridge, indications 

 of a time-interval between these limestone series. The 



* Ibid., vol. 42, pp. 68-70. 



t Correlation Table, 1895, p. 341. 



X Geol. Survey of Georgia, First Rep., 1 800-1. 



II Amer. Jotir. Sci., 3rd ser., vol. 46, p. 445-7. 



