Abstract
The conclusions of E. W. Galliher1 that glauconite is forming from biotite in Monterey Bay, and of John W. Gruner2 that the molecular structure of Bonneterre glauconite is similar to that of biotite from Mora, Minnesota, led me to test the possibility that Missouri glauconite has formed from biotite. Several years ago I observed3 that anauxite from the lone formation of California which had formed from biotite contained rutile needles similar to those in biotite, and studies of clay4 carried on by the Missouri Geological Survey afford evidence that titanium is concentrated along with aluminum during the change of flint clay to diaspore clay. The titanium content of glauconite, especially that present as rutile, seemed a logical starting point in this study. A survey of the published analyses of glauconite showed that little attention had been given to the titanium of glauconite, for only three or four record even a trace.
