E. A. Smith — Post-Eocene Formations of Alabama. 289 



(c) Along the western shore of Mobile Bay, just below Fras- 

 cati, the storms of last October washed away long stretches of 

 the bluff, and exposed the structure of the Mobile terrace in 

 the most perfect way. A section of this shows below the 

 recent surface sands, a yellowish loamy sand about five feet 

 thick ; then a layer of transition material consisting of yellow- 

 ish sands with lumps of gray clay one foot and a half ; then a 

 layer of lignite- from six to twelve inches, and below that 

 down to the level of low tide, and possibly still lower, six feet 

 or more of blue clay containing many stumps and limbs, or 

 roots, bituminized on the outside, but of the nature of yellow 

 rotten wood inside. The same blue clay is reached in wells at 

 maDy points on the Mobile terrace, at a distance from the 

 actual coast.* This is substantially the succession of strata that 

 may be seen along both the great rivers tributary to Mobile 

 Bay, as well as along the Chattahoochee. 



Along the smaller streams emptying into these larger rivers 

 and into the Gulf, the yellow loam and blue clay stratum are 

 rarely, if ever, seen, and the entire second terrace consists of 

 the gray sands mixed with pebbles in the lower parts. In the 

 southern parts of the State generally, and especially in the 

 southeastern, these gray sands form not only the second ter- 

 races of the creeks, but are also spread over the divides up to 

 altitudes of 100 feet above tide. Where this is the case the 

 streams rarely have swamps, but the pine-clad second-bottom 

 sandy plain reaches to the very brink of the channel. The 

 sands usually rest unconformably upou the red loam of the 

 Lafayette, though sometimes when this has been removed by 

 erosion, upon the underlying Tertiary formations. Along the 

 Chattahoochee River, and probably along some parts of the 

 Alabama also, these sands occur as a sort of upper second ter- 

 race, outside of and a few feet above the usual yellow loam 

 terrace. The growth on the sand terrace is almost exclusively 

 the long leaf pine, while on the true second terrace the growth 

 is much more varied. 



We have suggested the name of Ozark or Geneva sands for 

 these beds, which seem to correspond very closely with what 

 have been described by Mr. McGee in other States to the north 

 of Alabama. Here as there they occur along the streams, in 

 the lowlands, and over the divides, corresponding to the fluvial, 

 low level, and interfluvial phases of the Columbia formation. 

 In the lower part of Alabama, these beds lie as if spread upon 

 an undulating surface, and in this respect resemble the Lafay- 

 ette formation to be described below. They appear to have 

 been deposited upon a gradually emerging sea bottom, the last 



* Wherever penetrated in these wells the blue clay stratum is found to be 

 underlaid by white sands. 



