596 WALTER H. BUCHER 
water vapor in the atmosphere frequently has the properties of an 
emulsion colloid is well known. 
3. Hydroxides: The hydroxides of iron, manganese, and alumi- 
num occur in all three forms with the exception of the last named, 
which is, as far as I know, not found in spherulitic or analogous 
structures. Aluminum hydroxide has, however, little chance to 
occur in the pure state. ‘‘Meta-”hydroxides in concentrated 
solution are known to be in the emulsoid state’ and are widely 
distributed in that form in nature. 
4. Phosphates: Phosphatic odlites are common in our western 
phosphate beds. Concretions are widespread and some show radial 
crystalline structure. The colloid origin of certain phosphates 
has long been recognized.? Because of the emulsoid character of 
their sols the phosphates are classed with the “gelatinous salts.’ 
5. Barite: Odlites consisting largely of barite with small 
amounts of gypsum and selenite were described by Wuestner? and 
Moore! from oil wells in Hardin County, Texas. They are of 
special interest because at least some of them undoubtedly formed 
in the wells after they were equipped, since they are found inside the 
tubing in sizes which could never have passed through the small 
mesh of the screen... As the oil in the well has a temperature of 
125° F. and contains free sulphuric acid, they offer a good example 
of an unquestionable case of an inorganic production of odlites. 
Fortunately some of these odlites, as shown on the micrographs 
of Wuestner’s paper, Figs. 2-4, exhibit the same pattern of tubes 
radiating from the center which is so frequently seen in sections of 
sedimentary calcareous odlites’ and which Kalkowsky, in his 
Ostwald Wolfgang, Handbook of Colloid-Chemistry, translated by Martin H. 
Fischer (Philadelphia, 1915), p. 51. 
2 A. F. Rogers, ‘‘A Review of the Amorphous Minerals,” Jour. Geol., XXV (1017), 
530-33. 
3H. Wuestner, ‘“‘Pisolitic Barite,” Jour. Cincinnati Soc. Nat. Hist., XX (1906), 
245-50, 4 figs. 
4E. S. Moore, ‘‘Odlitic and Pisolitic Barite from the Saratoga Oil Field, Texas,” 
Bull. Geol. Soc. America, XXV (1914), 77-79. 
5E. S. Moore, ‘“‘Additional note on ‘The O@litic and Pisolitic Barite from the 
Saratoga Oil Field, Texas,’ ’’ Science, N.S., XLVI (1917), 342. 
6 For instance, in the odlites of the St. Louis limestone. They are also seen in 
two sections of bladderstones in the author’s possession. 
