PUBLICATIONS. OF 
tant are at or near the base, and at the top of the Selma Chalk. The 
phosphate-bearing member at the base of the series is known as the 
“‘EKutaw, Hamburg, Selma Belt” because it is well developed at those 
places. Forasimilar reason the phosphate-bearing member at the top 
of the series is known as the “ Livingston, Fort Deposit, Union Springs 
Belt.” In limited quantities phosphates have also been found in other 
parts of the same formation. Each of the principal phosphate hori- 
zons consists, not of one stratum, but of several different strata containing 
phosphates in various forms. They are extensively developed through- 
out the Cretaceous area, from the northwest part of the state to the 
Georgia border. 
The phosphates at the base of the Selma Chalk occur as nodules 
and phosphatic casts of fossils, as phosphatic sands and glauconites, 
or as calcareous marls containing more or less phosphate. The 
nodules are associated with numerous worn and rounded casts of 
Cretaceous fossils, such as ammonites, baculites, nautili, etc., which are 
also often highly phosphatic, as well as with many sharks’ teeth and 
bones of saurians. ‘These nodules and fossils are enclosed in a soft, 
calcareous matrix, and sometimes in glauconite. The nodules and 
some of the fossil casts are the richest phosphates found, and often 
contain from 4o per cent. to over 80 per cent. phosphate of lime. The 
phosphatic sands, glauconites and marls are much lower grade, con- 
taining from 1 to 20 per cent. of phosphate of lime, and often averag- 
ing not over 1 to 3 per cent., but they are in much larger quantities 
than the nodules. The phosphates of the ‘‘ Livingston, Fort Deposit, 
Union Springs Belt,” are similar to those of the lower horizon. 
The Tertiary strata, as well as the Cretaceous, sometimes contain 
phosphates, but they are less abundant, and are of lower grade. They 
occur mostly in the Lignitic, White Limestone and Claiborne members 
of this series, and are in the form of scattered nodules and phosphatic 
marls. 
It is shown that the phosphate deposits occur along lines of non- 
conformity, and that the fossil casts, etc., are all more or less worn. Pro- 
fessor Smith supposes the presence of the phosphates to be due to the 
phosphatization of fossil casts, marls, limestones, etc., during the forma- 
tion of these non-conformities, and the source of the phosphates he 
ascribes to the decay of animals and plants, and of phosphate-bearing 
rocks. He shows that though the phosphate localities rarely possess suf- 
ficient quantities of high-grade material to be profitably shipped, yet the 
