ON A BRACKISH WATER PLIOCENE FAUNA OF THE 

 SOUTHERN COASTAL PLAIN. 



By William Healey Dall, 



Curator, Division of Mollusks, United States National MiLseum. 



In Bulletin 5A, of the State survey, on the phosphates and marls 

 of Georgia by S. W. McCallie, page 87, 1896, attention is called to a 

 marl bed on the Satilla River by the following remarks: 



Several miles further up the river, on M5-. James P. King's estate, occurs an exten- 

 sive marl bed. The property on which the deposit is located is situated 6 miles 

 south of Atkinson, and of late years it has become quite a popular resort for fishing 

 parties, whose attention is usually attracted by the peculiar appearance of the 

 deposit. The principal exposure occurs at the base of a bluff, on the left bank of the 

 river, a few hundred yards north of the mansion house. The bluff, which is about 30 

 feet in height, shows the following geological section: 



Feet. 



Soil H 



Bluish clays 2 



Motley, sandy clays 10 



Light-colored, sandy clays 5 



Yellowish, sandy clays 4 



Laminated blue clays 2 



"White sand 1 



Blue clay 2^ 



Marl 2 



At the time of our visit only about 2 feet of the marl bed was exposed above the sur- 

 face of the water. However, detached fragments of the bank below this level show 

 that the bed attains a thickness at this point of 4 feet or more. The deposit con- 

 sists almost entirely of small bivalve shells, with a sandy clay matrix. Associated 

 with the shells are fragments of bones and what appear to be the remains of the cara- 

 paces of turtles and crabs. The marl has been used to a limited extent by Mr. King 

 as a fertilizer on various crops, and it is said to have given very satisfactory results. 

 It is evidently of much value, locally, as a fertilizer. However, it could not probably 

 be transported to any distance with profit. Another outcropping of the deposits 

 occurs about a mile farther up the river; but it here seems to be diminished in thick- 

 ness, and also contains more sand and clay. 



In 1911 the Hon. T. H. Aldrich examined some of this marl at the 

 suggestion of Mr. McCallie, and, recognizing that many of the spe- 

 cies were new and that the indications were that the fauna was of 



Proceedings U. S. National Museum, Vol. 46— No. 2023. 

 95278°— Proc.N.M.vol.46— 13 15 225 



