154 Papers from the Marine Biological Laboratory at Tortugas. 



The changes from sediments of one character to those of another were fre- 

 quently rapid, and during the entire time there was more or less intermingling of 

 different kinds of sediments, giving rise to the marls, impure limestones, shales, 

 and sands of this epoch. 



In the east and south central portions of the Peninsula the clay and sand 

 predominated during the earlier part of this epoch, while farther north and west 

 (also east on the Savannah River) similar deposits characterized the later stages. 

 The calcareous materials which are found now in the form of marls and limestones 

 were especially important in the area drained by the Apalachicola River, but they 

 were also deposited in smaller quantities farther south and east. Throughout the 

 period represented by the Apalachicola Group the conditions governing deposition 

 appear to have differed considerably in neighboring localities, but there was no 

 such abrupt variation as ma} - be found along the present coast. 



The facts recited in the preceding remarks indicate very shallow- 

 water conditions. 



FAUNAL CHARACTERS. 



Some of the faunal characters of the older formations of this group 

 are important. Coral reefs and massive corals which probably did not 

 form reefs were present. They have already been alluded to in the sec- 

 tion of this paper giving the stratigraphic distribution of reef corals, 

 but may be repeated. 



In Georgia fossil reef or massive corals have been reported from the 

 following localities: 



Decatur County: Flint River at Cherry Shoot, 3 miles below Bain- 

 bridge ; Blue or Russell Spring, 4 miles below Bainbridge ; Little 

 Horse Shoe Bend, about 0.75 mile below the preceding locality; 

 and Hales Landing, 7 miles below Bainbridge. 



Grady County: 4 miles northeast of Forest Falls; 9 miles a little 

 west of north of Whigham. 



Thomas County : 3 miles west of Metcalf ; 1 1 miles south of Thomas- 

 ville; 3 miles west of Boston; 4.5 miles south of Boston. 



Brooks County: 1.5 miles east of Quitman. 



Lowndes County: Withlacoochee River, about 3 miles below the 

 Valdosta Southern R. R. bridge; 2 miles northeast of Clyatts- 

 ville. 



Screven County: Old Jacksonboro near Bascom P. 0. 



In Florida the following localities are known: 



Gadsden County: The vicinity of River Junction. 



Wakulla County: The vicinity of Wakulla. 



Suwanee County: White Springs on the Suwanee River. 



Columbia County: 2 miles south of Lake City. 



Alachua County: Numerous localities from 2 miles to 6 miles north 



of the town of Alachua. 

 Hillsboro County: Ballast Point. 



These corals occur in each of the three local formations forming the 

 lower portion of the Apalachicola group, viz: the Chattahoochee, the 

 Hawthorne, and the Tampa. 



