600 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 51. 



settlement about 18 miles southeast of De Funiak Springs, Walton 

 Coimty, Florida. At Alum Bluff, Florida, this formation consists of 

 a lower bed of dark gray to gi-eenish f ossiliferous sand above which is 

 a steel gray unfossiliferous sandy clay to which Doctor Dall applied 

 the name ''Aluminous Clay," on account of the seepage from it of 

 alum-bearing water. 



The following is a list of species collected by George C. Matson on 

 the John Anderson farm, 1 mile south of Redbay, Florida, identified 

 by Dr. T. W. Vaughan ^ with his determination of the geologic 

 horizon: 



Tunitella variabilis Conrad. Crassatellitcs melinus Conrad. 



Dentalium altenuatum Say. Chmna ardnella'Limi&ews. (Jackson bluff 



Area staminea Say. var.) 



Pecten cf. eboreus Coni'ad. Cardium acutilaqueatum Conrad. 



Pecten madisonius Say. Verms rileyi Conrad. 



Horizon— Miocene. — Jackson's bluff, Coe's Mill, upper bed at 

 Alum Bluff. 



During the autumn of 1914, Dr. C. Wythe Cooke and the writer 

 visited Redbay, and obtained an additional collection of fossils near 

 the place from which Mr. George Matson in 1908 obtained the collec- 

 tion identified by Doctor Vaughan. The exact location of Mr. Mat- 

 son's collecting is on the Anderson farm, 1 mile south of Redbay, 

 while the later collection was at a bluff beneath a spring, in E. Gomil- 

 hon's field, about one-fourth mile east of Redbay. These two col- 

 lections furnish the material for this paper. 



According to Matson ^ 



The Choctawatchee marl attains a thickness of over 50 feet in the vicinity of Redbay, 

 Walton County, where it is exposed in some small ravines, and exceeds 30 feet on the 

 banks of Mill Creek near Holland Post Office, Leon County. However, from obser- 

 vation elsewhere, it appears probable that the average thackness is not more than 25 

 to 30 feet. It rises to the siu'face in a belt 6 to 12 miles in -width, extending from south- 

 ern Walton County eastward to Leon County. 



The following notes were taken in the vicinity of Redbay by Doctor 

 Cooke: 



The Choctawhatchee marl is a bluish-gray argillaceous sand containing many fossils. 

 Parts of it are micaceous. It outcrops in a bluff forming an escarpment which may 

 easily be traced. The access to the outcrops is usually difficult, owing to the growth 

 of dense tangled masses of vines and a covering of leaves and talus. An exposure of 

 about 10 or 15 feet was found beneath a spring called "Dripping Spring," in E. Go- 

 million's field, about one-fourth of a mile east of Redbay. The material consists of 

 blue argillaceous sand marl, replete with shells in the lower part but preserved only as 

 casts in the laminated upper part. Above this bed is a yellow incoherent sand, which 

 forms hill slopes. Springs issue from the top of the marl bed. 



The character of the matrix in which the fossil collection one-fourth 

 mile east of Redbay, Florida, was obtained, is as follows: 



1 Florida Geol. Survey, 2nd Ann. Rep., p. 117. 



2 Water Supply Paper 319, pp. 129-130. 



